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Purpose: Adenotonsillar hyperplasia causes upper airway obstruction, leading to obstructive sleep apnea. We reviewed the incidence of nocturnal enuresis in a population of children with adenotonsillar hyperplasia. In addition, we investigated the rate of resolution or improvement in enuresis following surgery for relief of adenotonsillar hyperplasia., Materials and Methods: We studied 86 consecutive prepubertal children, 46 boys and 40 girls, who underwent adenotonsillectomy. Severity of adenotonsillar obstruction was graded on a scale of 1 to 4. A questionnaire regarding voiding problems, including nocturnal enuresis, voids per day and daytime enuresis episodes, was filled out preoperatively and postoperatively by the patients and their parents., Results: Among the 86 patients who underwent adenotonsillectomy 36 (42%) had nocturnal enuresis. In patients with nocturnal enuresis the number of episodes was significantly less after adenotonsillectomy. Overall, 12 patients (33%) had complete resolution, 11 (31%) had significant improvement and 13 (36%) showed no change. In addition, we noted a significant decrease in daytime enuresis episodes and voids per day., Conclusions: Children with upper airway obstruction have a high rate of nocturnal enuresis that improves at twice the anticipated rate after treatment of the airway obstruction. In addition, we observed that daytime voiding dysfunction improves in these patients.

Aim: To determine if tamsulosin treatment prevents or decreases the incidence and severity of outlet obstruction-induced bladder dysfunction in rabbits., Materials and Methods: Male New Zealand White rabbits were treated with tamsulosin or vehicle for 4 weeks with treatments initiated 1 week prior to sham or obstruction surgery. Cystometry was done on anesthetized rabbits 21 days after surgery. The bladders were then removed, weighed, and prepared for in vitro whole bladder studies. Responses to 32 Hz field stimulation (FS), carbachol, phenylephrine, and KCl were measured., Results: Obstruction resulted in a significant increase in bladder weight, which was unchanged by tamsulosin treatment and a significant increase in micturition pressure in the vehicle-treated group but not in the tamsulosin-treated group. Compliance was significantly decreased in both obstructed groups. The vehicle-treated obstructed rabbits had a very sharp increase in intravesical pressure as the bladder reached capacity; this was not seen in the tamsulosin-treated obstructed rabbits. Tamsulosin did not change the pattern of modifications in contractile responses induced by bladder outlet obstruction., Conclusions: In vitro responses of vehicle and tamsulosin-treated obstructed rabbit groups in this study were similar. A greater micturition pressure was found for the vehicle-treated obstructed group than for the tamsulosin-treated obstructed group, which was probably due to decreased urethral resistance in the latter. On a functional basis, the higher compliance at capacity and decreased micturition pressure in the tamsulosin-treated obstructed group would be considered beneficial for bladder function., (Neurourol. Urodynam. (c) 2005 Wiley-Liss, Inc.)

Objective: To investigate the effects of hypercholesterolaemia (HC) on rabbit corpus cavernosa in vivo and in vitro, and evaluate the efficacy of vardenafil and sildenafil in normal and HC rabbits, as the phosphodiesterase-5 (PDE-5) inhibitors vardenafil and sildenafil are widely used for treating erectile dysfunction (ED) and most organic causes of ED are associated with vascular risk factors like HC., Materials and Methods: Male New Zealand White rabbits were randomly divided into two groups; 11 HC rabbits were fed a 2% cholesterol diet, and 12 age-matched control rabbits received a regular diet. After 12-14 weeks, erectile responses to intravenous sodium nitroprusside (SNP) and PDE-5 inhibitors were evaluated for 2 h in conscious rabbits. Penile length was measured and the area under the curve calculated. Relaxant responses of corpus cavernosal strips to electrical-field stimulation (EFS) were measured before and after exposure to PDE-5 inhibitors and the nitric oxide synthase inhibitor N'-nitro-L-arginine methyl ester., Results: HC rabbits had a lower erectile response to SNP than controls; in both control and HC rabbits there was a greater erectile response after simultaneous exposure to SNP and vardenafil, or SNP and sildenafil. However, the responses of the HC rabbits were still significantly less than those of the controls. Corpora from control rabbits responded to EFS with greater relaxations at all frequencies, except 1 Hz. Corpora from both HC and control rabbits had greater responses to EFS after exposure to vardenafil and sildenafil; N'-nitro-L-arginine methyl ester diminished the response to EFS., Conclusions: There was a significantly lower in vivo and in vitro erectile response in HC rabbits than in controls; erectile function measured in conscious rabbits can be used to assess quantitatively the efficacy of different agents, e.g. sildenafil and vardenafil, in pathological animals. In addition, both agents improve in vitro responses of erectile tissue from HC rabbits to EFS.

Objective: To examine regional responses of control and obstructed rabbit detrusor strips to electrical and adrenergic stimulation, and determine whether outlet obstruction causes regional variations in blood flow throughout the detrusor, as the detrusor smooth muscle of the bladder body has previously been considered homogeneous in its pharmacological properties., Materials and Methods: Fourteen male rabbits had the bladder outlet surgically obstructed for 2 weeks and were compared with 10 unoperated control rabbits. Blood flow was measured with the bladder empty and at capacity, using fluorescent microspheres. Paired dorsal and ventral strips were harvested from the midline equatorial detrusor and electrically and adrenergically stimulated., Results: Obstructed rabbits had significantly higher bladder capacities and bladder weights than control rabbits. Dorsal strips from both control and obstructed rabbits contracted in response to noradrenaline, whereas ventral strips relaxed. The addition of prazosin, a nonselective alpha1-adrenergic-receptor blocker, completely blocked the contraction in dorsal strips, but had no effect on responses of ventral strips. There was also a regional difference in response to electrical stimulation, with ventral strips generating significantly more tension than dorsal strips in both control and obstructed rabbits. There were no regional differences in detrusor blood flow. Obstruction resulted in significantly lower responses to all forms of stimulation, and significantly less blood flow throughout the detrusor., Conclusion: There are regional differences in adrenergic receptor function and response to electrical-field stimulation throughout control and obstructed rabbit detrusor, a region that was previously thought to be functionally homogeneous. These differences must be recognized and acknowledged to obtain accurate and reproducible data from in vitro studies of the bladder.

This study tested the hypothesis that morphine and other opiates cause urinary retention by activating mu opioid receptors in the midbrain periaqueductal gray (PAG) region. Selective mu, delta and kappa receptor agonists were microinjected into the PAG of urethane-anesthetized rats and the amplitude and incidence of bladder contractions were recorded during continuous saline infusion. Arterial pressure was monitored through a femoral artery catheter. Microinjection of the mu receptor agonist DAMGO into the ventrolateral PAG (vlPAG) suppressed volume-evoked bladder contractions completely. Bladder contractions ceased within 5 min of DAMGO injection and remained essentially undetectable for the rest of the 20 min recording period. Microinjection of the delta receptor agonist DPDPE into the vlPAG did not significantly affect either the amplitude of bladder contractions or the time interval separating contractions. The kappa receptor agonist U-69593 caused no discernible change in amplitude but increased the interval between bladder contractions significantly. Microinjection of DAMGO, DPDPE or U-69593 into the lateral or dorsolateral PAG columns was ineffective. DAMGO injection into the vlPAG increased arterial pressure whereas DPDPE and U-69593 produced a small but significant depressor response. These data support the hypothesis that mu and kappa receptors in the vlPAG participate in the micturition reflex.

Purpose: We investigated the effects of the combination of bladder outlet obstruction and diabetes mellitus on in vitro rat bladder body strip function., Materials and Methods: Longitudinal strips were removed from ventral and dorsal detrusor of age matched control, 2-week diabetic, 2-week obstructed and 2-week obstructed diabetic rats. Contractile responses to electrical field stimulation, carbachol, adenosine triphosphate, KCl and phenylephrine, and relaxations in response to norepinephrine and isoproterenol were measured., Results: Bladders from diabetic, obstructed and obstructed diabetic rats were 1.6-fold, 2.6-fold and 3.6-fold heavier than those from controls. Responses of bladder strips from diabetics to all stimuli were similar to those of controls. Strips from obstructed rats were significantly less responsive to norepinephrine than those from controls or diabetics and strips from obstructed diabetics were significantly less responsive to norepinephrine and isoproterenol than those from all other groups. Strips from obstructed diabetics had significantly decreased responses to field stimulation, while responses to carbachol were decreased to a lesser extent. Responses of strips from obstructed rats to field stimulation were also decreased compared with controls but were significantly greater than those of the obstructed diabetic group. Responses to adenosine triphosphate, KCl and phenylephrine were similar in all groups., Conclusions: The combination of outlet obstruction and diabetes mellitus causes significant increases in bladder mass compared with either diabetes or obstruction alone. Bladder strips from obstructed diabetics show characteristics of denervation accompanied by alterations in beta-adrenergic function, suggesting that the coexistence of outlet obstruction and diabetes increases the rate of development of bladder decompensation.

Purpose: We mapped the regional distribution of alpha1 and beta-adrenergic receptors (ARs) in rabbit ventral and dorsal bladder, and characterized the alpha1-AR subtypes responsible for norepinephrine induced contraction of rabbit dorsal detrusor smooth muscle., Materials and Methods: Responses to norepinephrine in the absence and presence of adrenergic antagonists were measured in strips taken from clearly defined regions of male rabbit ventral and dorsal bladder., Results: In the absence of antagonists ventral strips from the bladder body relaxed in response to norepinephrine, while those from the ventral base contracted. Dorsal strips from the bladder dome also relaxed in response to norepinephrine but dorsal strips from the mid and lower body, and the base contracted. All contractile responses were antagonized by incubation with prazosin. Characterization of the alpha-AR subtypes present in dorsal strips from the mid and lower bladder body using BMY 7378 (8-[2-[4 to 2(-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro [4,5] decane-7,9-dione dihydrochloride), chloroethylclonidine, 5-methylurapidil and WB 4101 (2-(2,6-dimethoxyphenoxyethyl)-aminomethyl-1,4-benzodioxane) suggested that the alpha1-AR subtype responsible for the contraction is the alpha1A or alpha1L-AR., Conclusions: The male rabbit bladder contains at least 4 heterogeneous regions with differing functional responses to adrenergic stimulation, that is 1) the dorsal and ventral dome, where beta-ARs predominate, 2) the ventral detrusor, where beta-ARs predominate, 3) the dorsal detrusor, where alpha1-ARs predominate, and 4) the dorsal and ventral bladder neck, where alpha1-ARs predominate.

Purpose: We investigated the relationship of bladder mass to responses to electrical field stimulation and adrenergic agonists in diabetic rat bladders., Materials and Methods: Longitudinal strips were removed from the ventral and dorsal detrusor of age matched control, 2-month diabetic and sucrose drinking rats. Contractile responses to electrical field stimulation, KCl and phenylephrine, and relaxation in response to norepinephrine and isoproterenol were measured., Results: Bladders from sucrose drinking and diabetic rats weighed significantly more than those of controls. Diabetic rats were divided into 2 groups with the bladder weighing less than or greater than 265 mg. Strips from small diabetic bladders were generally more responsive to field stimulation and norepinephrine than those from control or sucrose drinking rats. Conversely decreased function was especially apparent in dorsal strips from large diabetic bladders. Ventral strips were significantly more sensitive to the relaxant actions of norepinephrine and isoproterenol than dorsal strips., Conclusions: Our results suggest that the responsiveness of diabetic rat bladder to electrical field stimulation and adrenergic agonists is related to bladder mass, analogous to observations after partial outlet obstruction. Decreased function was particularly apparent in dorsal strips from diabetic rats with a large bladder.

Studies were done to investigate the actions of ACTH on the expression of CYP2D16 in the guinea pig adrenal cortex. Guinea pigs were treated with ACTH for 1, 3, or 7 days. In addition, some animals received ACTH for 7 days and were then untreated for an additional 3 or 7 days to test for reversibility of ACTH actions. ACTH treatment caused a time-dependent decrease in the rates of adrenal microsomal bufuralol metabolism, a CYP2D-catalyzed reaction; hepatic bufuralol metabolism was unaffected by ACTH. Adrenal enzyme activity was significantly reduced by ACTH within 1 day and decreased by 80% after 7 days. Western blotting and in situ hybridization analyses revealed corresponding declines in adrenal CYP2D16 protein and mRNA concentrations. Nuclear runoff assays indicated that ACTH treatment inhibited CYP2D16 expression at the transcriptional level. Adrenal 17 alpha-hydroxylase activities were increased by ACTH treatment, but CYP17 protein concentrations were not affected. Following cessation of ACTH administration, the rates of adrenal bufuralol metabolism and CYP2D16 protein and mRNA concentrations returned to control levels within 7 days. The results demonstrate that ACTH has a relatively rapid and reversible effect to inhibit adrenal CYP2D16 transcription, thereby decreasing adrenal xenobiotic metabolism. Thus, the actions of ACTH on CYP2D16 expression are opposite to those on other adrenal p450 isozymes, indicating unique regulatory mechanisms., (Copyright 2003 S. Karger AG, Basel)

Experiments were done to evaluate the role of sex hormones in the functional development of the rat urinary bladder. Rats were orchiectomized or ovariectomized at 30 (prepubertal) or 70 (postpubertal) days of age and bladders were removed 1 month later. An additional group of immature male and female rats was used in which the bladders were removed at 30 days of age. There were only minor differences in contractile responses of bladder strips from any group to electrical field stimulation, ATP, carbachol, or KCl compared to age-matched controls. There were no differences in responses of bladder strips from immature females or males to the adrenergic agonists, isoproterenol, norepinephrine, or methoxamine. Bladders from the pre- and postpubertally castrated rats and their controls relaxed fully in response to isoproterenol, but strips from prepubertally castrated rats relaxed significantly less in response to norepinephrine than those from other groups. Approximately one half of the bladder strips from prepubertally castrated rats failed to relax by at least 50% in response to norepinephrine; these same strips responded to methoxamine with exaggerated contractions. Our data indicate that the normal development of rat bladder alpha-adrenergic responsiveness is adversely altered by prepubertal castration. We postulate that this may result from an alteration in the relative expression of alpha(1)-adrenergic receptor subtypes., (Copyright 2003 S. Karger AG, Basel)

Purpose: Experiments were done to evaluate the functional effects of neonatal diethylstilbestrol (DES) treatment on bladder function in male and female Noble rats., Materials and Methods: At 5 months after neonatal DES bladders were removed and weighed. Ventral and dorsal bladder strips were prepared to evaluate the effects of neonatal DES on contractile responses to electrical field stimulation, carbachol, adenosine triphosphate, phenylephrine and KCl. Relaxant responses to the catecholamines arterenol (norepinephrine), epinephrine and isoproterenol were also monitored., Results: Neonatal DES resulted in significant increases in bladder mass in males and females. Contractile and relaxant responses were largely unchanged by neonatal DES treatment and the only change observed was a decreased response of ventral strips from male neonatal DES rats to 4 and 8 Hz. stimulation. Ventral strips from male control and neonatal DES rats responded to field stimulation and carbachol with significantly greater responses than dorsal strips and were more sensitive to the relaxant actions of norepinephrine and epinephrine., Conclusions: The data confirm that neonatal DES causes infravesical obstruction. However, in contrast to published reports of the effects of surgically induced mild outlet obstruction, neonatal DES treatment has little effect on in vitro bladder strip contractile or relaxant function. Thus, the neonatal DES treated rat does not seem to be a useful model in which to study the in vitro effects of partial outlet obstruction on the bladder.

Purpose: The effects of experimental partial bladder outlet obstruction on the bladder response to nerve stimulation and contractile agonists have been well characterized. Mildly obstructed bladders have small increases in mass and increased contractile responses to electrical field stimulation. More severely obstructed bladders become decompensated with large increases in mass and decreased functional responses. Little is known about relaxant mechanisms after obstruction. We investigated the relationship of the increase in rat bladder mass induced by outlet obstruction and responses to alpha and beta-adrenergic stimulation., Materials and Methods: Male Sprague-Dawley rats were divided into 3 groups, namely control, sham operated and obstructed. Surgical obstruction was done by tying a 2-zero silk ligature around the urethra. The ligature was placed around the urethra and removed in sham operated rats. At 2 and 6 weeks bladders from all groups were harvested, weighed and cut into strips. Contractile responses to electrical field stimulation and norepinephrine in the presence of propranolol were measured. Relaxant responses to norepinephrine and isoproterenol were measured after pre-contraction with KCl., Results: All strips from control and sham operated rats relaxed completely in response to norepinephrine. Obstructed bladders that weighed 2 to 3-fold more than control or sham operated bladders also relaxed. In contrast, bladders that were 5 to 10-fold heavier failed to relax by at least 50% in response to norepinephrine, independent of duration of bladder outlet obstruction. These were called nonresponders. Two week nonresponders relaxed completely in response to isoproterenol, but 6-week nonresponders did not, suggesting that the duration of decompensation is important. All nonresponders relaxed in response to pinacidil (Sigma-Aldrich Corp., St. Louis, Missouri). Nonresponders tended to contract in response to norepinephrine in the presence of propranolol. Strips from the other rats were less responsive, suggesting an increase in alpha1-receptors with decompensation. Contractile responses to field stimulation were increased in obstructed strips that relaxed to norepinephrine, while responses of nonresponders were decreased compared with controls and sham operated rats., Conclusions: Severely obstructed bladders had an increase in mass and a decreased response to field stimulation, indicative of decompensation. This response was accompanied by decreased ability to relax to beta-agonists and an increased response to alpha-agonists. These changes were not seen in smaller, compensated bladders. Our findings suggest a change in detrusor alpha1 and beta-adrenergic receptor density. An increase in detrusor alpha-receptors may explain the clinical efficacy of alpha-blockers in alleviating irritative voiding symptoms in men with benign prostatic hyperplasia.

Purpose: Bladder outlet obstruction leads to bladder enlargement and subsequent decreases in contractile function in vivo and in vitro. We determined whether there were regional differences in bladder wall properties and in vitro contractile responses after 2 weeks of bladder outlet obstruction., Materials and Methods: Male rabbits underwent cystometry. The bladder was then filled to 40 ml. and the surface was marked with 2-zero silk knots placed approximately 1 cm. apart. The distance between the knots was measured at 20, 40 and 80 ml. The animals then underwent the creation of surgical obstruction. After 2 weeks the obstruction was removed. Cystometry and measurements were repeated and strips were obtained from defined dorsal and ventral areas. Contractile responses to electrical field stimulation, adenosine triphosphate, carbachol and KCl were determined and compared with strips from unobstructed controls., Results: In vivo expansion during bladder filling occurred evenly throughout the bladder wall in controls and the contractile response to all stimuli was similar in ventral and dorsal strips. After 2 weeks of bladder outlet obstruction the upper dome expanded to a significantly higher degree than the lower bladder body. The response to all stimuli was significantly reduced after bladder outlet obstruction and there was a significantly decreased response to all stimuli in dorsal compared with ventral strips. Strips from the dorsal midline showed a relaxation response to electrical field stimulation at low frequencies, whereas all ventral strips contracted., Conclusions: Functional remodeling after bladder outlet obstruction is a process that does not occur to the same extent throughout the bladder. The obstructed bladder is an inhomogeneous organ with significant regional differences in mechanical and pharmacological properties.

Objectives: To examine whether bladder smooth muscle dysfunction after outlet obstruction could be altered by treatment with aspirin. Long-term outlet obstruction causes contractile and metabolic dysfunction of the bladder in vivo and in vitro. The evidence is growing that a decrease in bladder perfusion is an important cause of this phenomenon. The platelet aggregation inhibitor, acetylsalicylic acid (aspirin), has been used to improve perfusion of the heart for decades., Methods: Ten male New Zealand white rabbits were obstructed for 4 weeks. Five rabbits received no further treatment (Obs), and 5 rabbits received 2 mg/kg/day aspirin (Obs+aspirin), administered by an osmotic pump implanted subcutaneously 1 week before the surgical obstruction. The bleeding time was measured to confirm the effectiveness of the aspirin treatment. Three different control groups were created: sham-operated rabbits, unobstructed rabbits with pumps containing DMSO (vehicle), and unobstructed rabbits with pumps containing aspirin. The contractile responses of bladder strips to field stimulation, adenosine triphosphate, carbachol, and KCl were determined. A section of each detrusor tissue was fixed in formalin and used to determine the smooth muscle and collagen (connective tissue) volume fraction., Results: No differences were found in the bladder weights or responses to stimuli in the different control groups, which were therefore combined. Partial bladder outlet obstruction caused significant increases in the bladder weight of the obstructed animals (Obs+aspirin, 10.15 +/- 0.87 g; Obs, 10.17 +/- 0.88 g; and controls, 2.87 +/- 0.21 g). The aspirin treatment increased the bleeding time from 1.7 +/- 0.3 minutes to 3.3 +/- 0.1 minutes. The responses to field stimulation were significantly reduced in all of the obstructed rabbits. However, the responses of the bladder strips from the Obs rabbits to field stimulation were impaired to a significantly greater degree than were those from the Obs+aspirin rabbits. The response to 32-Hz stimulation was reduced by 86% in the Obs group but by only 64% in the Obs+aspirin group. The responses to carbachol were significantly reduced by 62% in the strips from the Obs rabbits, but the responses of the strips from the Obs+aspirin rabbits were similar to the responses of the strips from the controls. The responses to KCl and adenosine triphosphate were reduced, although they just failed to achieve statistical significance using Bonferroni's analysis. The ratio of smooth muscle and connective tissue shifted slightly toward smooth muscle after 4 weeks of obstruction, but no difference was found with or without aspirin treatment., Conclusions: Low-dose aspirin has a small but significant protective effect on the contractile dysfunction induced by bladder outlet obstruction in rabbits, although the increase in bladder mass was not altered. Bladders of the same weight showed improved responses to all forms of stimulation after pretreatment with aspirin. Already used by millions of patients with heart diseases, aspirin could be a useful protection against contractile dysfunction of the obstructed bladder.

Previous investigations demonstrated that CYP2D16 was expressed at high levels in guinea pig adrenal microsomes. The studies presented here were done to determine whether adrenal metabolism of bufuralol (BUF), a model CYP2D substrate, was similar to that in the liver. Guinea pig adrenal microsomes converted BUF to 1'-hydroxybufuralol (1'-OH-BUF) as the major metabolite and smaller amounts of a compound identified as 6-hydroxybufuralol (6-OH-BUF). In contrast, 6-OH-BUF was the major product formed by hepatic microsomal preparations. The apparent Km values were similar for 1'-OH-BUF and 6-OH-BUF production in each tissue. Quinidine, a selective CYP2D inhibitor, decreased the production of both BUF metabolites equally in liver and adrenal microsomes. Cortisol also caused equivalent decreases in the rates of 1'-OH-BUF and 6-OH-BUF formation by adrenal microsomes, but had no effect on hepatic BUF metabolism. Although both BUF metabolites may be produced by CYP2D16, unknown factors appear to effect some differences in the catalytic characteristics of BUF metabolism in adrenal and liver. The large amount of 6-OH-BUF produced distinguishes BUF metabolism in guinea pigs from that in other species previously studied., (Copyright 2001 S. Karger AG, Basel)

Studies were done to evaluate the effects of alpha-tocopherol deficiency in rats on the fatty acid composition and sensitivity to lipid peroxidation (LP) of mitochondria and microsomes from adrenal glands, testes, and livers. In control (alpha-tocopherol-sufficient) animals, adrenal concentrations of alpha-tocopherol were approximately 10 times greater than those in livers and testes. Dietary deficiency of alpha-tocopherol for 8 weeks decreased adrenal and hepatic concentrations by 80-90% and testicular concentrations by approximately 60-70%. Incubation of testicular or hepatic mitochondria and microsomes from control rats with FeSO(4) (1.0 mM) caused a time-dependent stimulation of LP as indicated by the formation of thiobarbituric acid reactive substances (TBARS); the rate of TBARS production increased in preparations from alpha-tocopherol-deficient animals. TBARS formation was not demonstrable in adrenal mitochondria or microsomes from alpha-tocopherol sufficient rats, but reached high levels in alpha-tocopherol-deficient preparations. The fatty acid composition of mitochondria and microsomes was tissue-dependent. In particular, arachidonic acid comprised approximately 40% of the total fatty acids in adrenal membranes, but only 20-25% in testes and livers. alpha-Tocopherol deficiency increased oleic acid concentrations in adrenal and hepatic mitochondria and microsomes but not in testes. In all three tissues, linoleic acid concentrations decreased by approximately 50%, but arachidonic acid levels were unaffected by alpha-tocopherol deficiency. The results indicate a close relationship between tissue sensitivity to LP in vitro and alpha-tocopherol concentrations. Nonetheless, any oxidative stress in vivo caused by alpha-tocopherol deficiency seems to spare arachidonic acid in mitochondria and microsomes but decreases linoleic acid concentrations. It is possible that because of the important physiological functions of arachidonic acid, metabolic adaptations serve to maintain membrane content during periods of oxidative stress.

Purpose: Previous studies have shown that the initial reaction of the rabbit bladder to partial bladder outlet obstruction is increased blood flow at day 1 and a return to baseline blood flow at 1 week. Mucosal and muscle blood flow followed this pattern but mucosal blood flow was always 4 to 5-fold greater. In this study we examined the effect of 4 weeks of outlet obstruction on bladder blood flow and correlated it with the severity of bladder contractile dysfunction., Materials and Methods: A total of 14 male New Zealand White rabbits underwent partial outlet obstruction creation by standard methods. After 4 weeks the rabbits were anesthetized, and blood flow to the muscle and mucosa was determined by standard fluorescent microsphere technique. A section of each detrusor was used for in vitro contractility studies. Contractile responses to field stimulation, carbachol and potassium chloride were determined. A section of each detrusor tissue was fixed in formalin and used to determine the smooth muscle volume fraction., Results: Four weeks of partial bladder outlet obstruction caused a significant and variable increase in bladder weight and a decrease in blood flow to bladder muscle without changes in the blood flow to mucosa. There was a clear correlation between the severity of contractile dysfunction, bladder weight and the magnitude of the decrease in blood flow in muscle. The smooth muscle volume fraction remained stable at approximately 40%., Conclusions: Bladder decompensation was associated with decreased blood flow to bladder smooth muscle. Because compensated obstructed bladders with relatively normal contractile function are also hypertrophied but have normal blood flow, decreased blood flow in decompensated bladders is not simply a response to bladder hypertrophy. From this study we hypothesize that decreased blood flow to bladder smooth muscle is an etiological factor in bladder contractile dysfunction (bladder decompensation) secondary to partial outlet obstruction.

Voiding dysfunction is common, and patients with urge incontinence, frequency/urgency syndromes, and chronic urinary retention are challenging to treat once conservative therapies (such as pharmacologic agents, pelvic floor rehabilitation, and intermittent catheterization) have been exhausted. Sacral nerve stimulation (SNS) is a new, minimally invasive, reversible therapy for the management of refractory voiding dysfunction and provides an attractive therapeutic alternative for patients with this condition. In this review, the role of SNS in the management of voiding dysfunction is examined critically, and the efficacy, risks, and benefits of this new modality are evaluated.

1. Experiments were done to determine the influence of gender and the oestrous cycle on rat urinary bladder contractility in response to cholinergic stimulation. 2. Bladder strips from female rats responded to high frequency stimulation with smaller contractile responses than did strips from males, and to low concentrations of carbachol with greater responses. The decreased responsiveness of bladder strips from female rats to electrical field stimulation can be primarily attributed to the rats in the oestrous stage of the oestrous cycle. 3. Bladder strips from female rats in all stages of the oestrous cycle were more sensitive to carbachol than those from males, but there were no differences in sensitivity to electrical field stimulation. 4. The contractile responses of strips from both male and female rats to carbachol were antagonized by muscarinic antagonists with the following rank order of affinity (pA(2)) estimates: 4-DAMP>>pirenzepine>methoctramine, suggesting that the receptor mediating contraction was the M3 subtype. There were no differences in pA(2) values between bladder strips from male and female rats. 5. The data indicate that responsiveness of bladder strips to electrical field stimulation and carbachol is altered in female rats in the oestrous stage of the oestrous cycle. Furthermore, gender influences the sensitivity of rat bladder to muscarinic stimulation.

Extractive and chromatographic separations were performed on V-1326, a chloroform extract from the bark of Prunus africana (also referred to as Pygeum africanum), which is used to treat the symptoms associated with benign prostate hyperplasia (BPH). The relative amounts of eleven identified constituents in crude V-1326 and in separated fractions were determined using gas chromatographic analysis. The ability of V-1326 and its separated fractions to inhibit ferrous ion-induced stimulation of lipid peroxidation in microsomal preparations from rabbit livers was evaluated. The extract, V-1326, and fractions containing high levels of myristic acid potently inhibited lipid peroxidation.

1. Isoproterenol relaxed KCl-precontracted rat bladder strips with a pD2 of 7.21 leaving a residual contractile response of 3.2% after 30 microM. The selective beta1-agonist, T-0509 (pD2 : 6.24, 10.1% residual contraction after 100 microM), beta2-agonist, terbutaline (pD2 : 5.43, 13.7% residual contraction after 100 microM), and beta3-agonists, BRL 37344A (pD2 : 6.60, 17.3% residual contraction after 100 microM), and SR 58611A (pD2 : 5.15, 34.0% residual contraction after 100 microM), also relaxed bladder strips. 2. The relaxant response to isoproterenol was weakly but significantly antagonized by 1 microM propranolol which produced a 3 fold shift of the concentration-response curve to the right, and significantly antagonized by the beta1-selective antagonist, metoprolol (10 microM, 3 fold shift), and the beta2-selective antagonist, butoxamine (100 microM, 6 fold shift). A combination of 10 microM metoprolol and 100 microM butoxamine caused a 15 fold shift of the concentration-response curve for isoproterenol to the right. Incubation with the beta3-antagonist, SR 59230A (1 microM), caused a 6 fold shift of the concentration response curve for isoproterenol to the right. 3. The non-conventional partial agonist, CGP 12177A, weakly relaxed KCl-precontracted bladder strips (pD2 : 3.31, 51.3% residual contraction after 300 microM); the relaxation was resistant to blockade by 1 or 10 microM propranolol. 4. In the presence of 200 microM propranolol, CGP 12177A (20 microM) or SR 59230A (10 microM) antagonized surmountably the relaxant effects of BRL 37344A. 5. The data suggest that rat urinary bladder body contains beta1, beta2, and beta3-adrenoceptors, all of which mediate relaxation.

Previous reports have noted high levels of lipid peroxidation (LP) in vitro in a variety of adrenocortical preparations. However, we have observed that susceptibility to adrenal LP seems to vary considerably from species to species. The current study was done to confirm these apparent species differences in adrenal LP in vitro and to determine if they were attributable to differences in alpha-tocopherol content. Incubation of mitochondrial or microsomal preparations from guinea pig or rabbit adrenal glands with ferrous ion (Fe2+) caused a time-dependent increase in the formation of thiobarbituric acid reactive substances (TBARS) accompanied by depletion of alpha-tocopherol. By contrast, incubation of adrenal mitochondria or microsomes from rats or monkeys with Fe2+ had little or no detectable effect on TBARS and basal adrenal alpha-tocopherol levels were five to ten-fold greater than those in guinea pigs or rabbits. In addition, there was little change in alpha-tocopherol concentrations during incubation of rat or monkey adrenal tissue. Dietary alpha-tocopherol deficiency in rats reduced adrenal alpha-tocopherol to concentrations approximating those in guinea pigs. Incubation with Fe2+ induced high levels of TBARS in adrenal mitochondria and microsomes from the alpha-tocopherol deficient rats. Conversely, dietary alpha-tocopherol supplementation in rabbits increased adrenal alpha-tocopherol levels and prevented Fe2+ induced TBARS formation in mitochondria and microsomes. The results indicate that there are large species differences in adrenal susceptibility to LP in vitro and that these differences are at least partly attributable to species differences in adrenal alpha-tocopherol concentrations.

Studies were done to determine the effects of ACTH treatment on adrenal alpha-tocopherol (alpha-T) concentrations in female rats. Administration of dexamethasone (DEX) to inhibit endogenous ACTH secretion increased whole adrenal alpha-T levels as well as the fractional amount in adrenal cytosol. Adrenal ascorbic acid (AA) concentrations were unaffected by DEX. DEX treatment also had no effect on hepatic AA content but decreased alpha-T concentrations in the liver. The subcellular distribution of alpha-T in the liver was not altered by DEX. Administration of ACTH to DEX-treated animals decreased adrenal alpha-T content and restored the pattern of subcellular distribution to that seen in controls. ACTH had no effect on hepatic alpha-T concentrations or subcellular distribution. ACTH treatment also had no effect on AA concentrations in adrenals or livers. The results demonstrate that ACTH has a role in the regulation of adrenal alpha-T but the mechanism(s) involved remain to be determined. The data also indicate that glucocorticoids such as DEX directly influence hepatic alpha-T levels independent of their effects on ACTH secretion.

Chronic bladder distension occurs after partial outlet obstruction and can lead to decompensation and impaired function. To quantify the degree of chronic bladder distension, we previously defined the zero pressure volume (ZPV), the largest contained volume at zero transmural pressure. In the current study, we investigated the short- and long-term effects of outlet obstruction and de-obstruction on chronic distension and passive bladder filling mechanics. Voiding patterns were measured 10 days (short term) or 6 weeks (long term) after partial bladder outlet obstruction and the bladders were tested in vitro at that time. De-obstructed bladders were obstructed for 6 weeks, and voiding patterns were measured 10 days or 6 weeks after de-obstruction, followed by in vitro testing. Mean voided volume was increased in de-obstructed bladders but not obstructed bladders. The volume of urine in the bladder at euthanasia was greater than mean voided volume in obstructed bladders and less than mean voided volume in de-obstructed bladders, indicating large residual urine in the obstructed bladders. ZPV was significantly increased only after long-term obstruction or de-obstruction. Similarly, intravesical pressure and mean bladder wall stress were increased only after long-term obstruction or de-obstruction. We conclude that tissue remodeling occurs in the bladder wall after long-term obstruction, possibly both as a result of and leading to chronic overdistension and high residual urine. Tissue remodeling occurs in the bladder wall after long-term de-obstruction, possibly due to large voided volumes. Neurourol. Urodynam. 18:659-671, 1999., (Copyright 1999 Wiley-Liss, Inc.)

Purpose: To investigate the influence of age and effect of increased outlet resistance on the ability of rabbit bladders to empty in response to various methods of stimulation., Materials and Methods: Bladders from six-month-old (young) and three-year-old rabbits (aged) were mounted in an in vitro whole organ bath system and filled with 15 ml. saline. The ability of the bladders to empty against low outlet resistance (LOR) and high outlet resistance (HOR) in response to field stimulation, bethanechol, and KCl was measured. The following parameters were measured: intravesical pressure and volume emptied. From these, flow rate, power, and external mechanical work were calculated., Results: Maximum isometric pressure did not change with age. All bladders emptied with increased pressure and decreased flow rate at HOR. The young bladders generated a greater maximum power in response to bethanechol and KCl than the aged bladders at both outlet resistances, and maximum power did not change with increased resistance. The aged bladders did less work and emptied significantly less than the young bladders at the HOR., Conclusions: The aged rabbit bladders were unable to maintain the bladder contraction long enough to empty completely through an increased outlet resistance. Because maximum power remained constant when the outlet resistance was increased, it might be useful clinically to determine the emptying ability of the urinary bladder, independent of changes in outlet resistance. In addition, bladder work could be used to evaluate bladder function if the volume emptied is also taken into consideration.

1. The effects of phosphodiesterase (PDE) inhibition and forskolin pretreatment on the contractile responses of guinea-pig urinary bladder strips to electrical field stimulation, carbachol, ATP and KCl were studied. 2. Inhibition of cyclic AMP-specific PDE4 isozymes by rolipram significantly reduced the contractile response of bladder strips to field stimulation. Rolipram also suppressed the contractile response to low concentrations of carbachol, but potentiated the response to high concentrations. The contractile response to ATP was significantly reduced by rolipram treatment, but that to KCl was unaltered. 3. Inhibition of cyclic GMP-specific PDE5 isozymes by zaprinast had no effects on the contractile response of bladder strips to field stimulation, ATP or KCl. Zaprinast suppressed the contractile responses to 1 microM carbachol and potentiated the response to high concentrations. 4. Contractile responses to field stimulation and to carbachol after pretreatment with the adenylyl cyclase activator, forskolin, were qualitatively similar to those caused by rolipram treatment. beta-Adrenoceptor blockade with propranolol partially reversed the inhibitory effects of rolipram on the response to field stimulation. 5. Rolipram significantly reduced the contractile response of bladder strips from sensitized guinea-pigs to ovalbumin challenge, but zaprinast was ineffective. PDE inhibition had similar effects on the responsiveness of control and of sensitized guinea-pig bladder strips to field stimulation, carbachol, ATP and KCl. 6. The data suggest that the contractile response of guinea-pig bladder strips can be modified by increases in cyclic AMP levels.

Purpose: To investigate the effect of independently inhibiting calcium influx from extracellular sources and calcium release from intracellular stores on the ability of the urinary bladder to generate pressure and empty., Materials and Methods: Rabbit bladders were mounted in an in vitro whole organ bath and filled with 15 ml. saline. Each bladder was incubated separately in Tyrode's solution, with diltiazem (10 microM), to block extracellular calcium influx, or with thapsigargin (40 microM) and ryanodine (80 microM), to block the uptake and release of calcium from the sarcoplasmic reticulum. The bladder was then stimulated isometrically with field stimulation (32 Hz), and to empty with field stimulation and with bethanechol (250 microM), independently. During stimulation, transmural pressure and volume emptied were measured. From these, flow rate, power, and external mechanical work were calculated., Results: In the presence of diltiazem, the time to maximal pressure decreased while the rate of pressure generation increased. This results from increased participation of intracellular calcium release, which occurs rapidly and near the smooth muscle filaments, decreasing the diffusion time. In the presence of thapsigargin and ryanodine the maximal rate of pressure generation was decreased, due to the increased diffusion time required for calcium to move to the muscle filaments from extracellular sites., Conclusions: The current study demonstrates that bladder pressure generation and emptying are dependent upon both an influx of calcium through L-type calcium channels (inhibited by diltiazem) and the stimulated release of calcium from the SR (inhibited by thapsigargin and ryanodine).

Bladder outlet obstruction induces severe changes in urinary bladder function and metabolism. These changes are characterized by significant reductions in the ability of the in vitro whole bladder to generate pressure and to empty. Metabolically, partial outlet obstruction induces a shift from oxidative to anaerobic metabolism. The decreased oxidative metabolism is mediated in part by significant decreases in mitochondrial substrate metabolism, which in turn is correlated with decreased activity of 2 important mitochondrial enzymes: citrate synthase and malate dehydrogenase. The present study was designed to evaluate mitochondrial function by studying the incorporation of 14C-adenine into high-energy phosphates (ATP, AMP, and ADP). Mild partial outlet obstructions were created by surgically placing silk ligatures loosely around the bladder neck. The results of these studies demonstrate that after 60 min incubation in oxygenated medium containing glucose + 1uCi14C-adenine, 1) There was no significant differences in the total AMP, ADP, and ATP concentrations measured in bladders taken from controls, 7- and 14-day obstructed rabbits; 2) there was no effect of obstruction on either the concentration of 14C-AMP in the tissue or in the ratio of hot to cold AMP; and 3) there was a 50% decrease in the concentration of 14C-ADP and a 70% decrease in the concentration of 14C-ATP in the bladder smooth muscle obtained from obstructed tissue (from both 7- and 14-day obstructions) compared to concentration in the control bladder smooth muscle. These results confirm the previous finding that obstruction did not reduce the rate of incorporation of adenine to AMP within the obstructed bladder smooth muscle and extends these studies to identify a significant reduction in the synthesis of both ADP and ATP. These results support the hypothesis that partial outlet obstruction induce a major dysfunction in mitochondrial function, both in the ability to oxidize substrates and in the ability to generate ATP.

Tadenan (Debat Laboratories, France) is a plant extract used in Europe for the treatment of micturition disorders associated with benign prostatic hypertrophy (BPH). Prior studies demonstrated that pretreatment of rabbits with Tadenan significantly reduced the contractile dysfunction observed after 2 weeks of partial outlet obstruction. The specific aim of the present study was to determine the effect of Tadenan therapy following the creation of partial outlet obstruction. Two sets of experiments were performed: one with mild and the other with severe outlet obstruction. For both sets of experiments, male New Zealand rabbits (3-5 kg) were separated into 3 groups of 5 rabbits each. Each rabbit in groups 1 and 2 was obstructed using standard methodology. Rabbits in group 3 served as controls and did not receive any surgery. After 2 weeks, each rabbit in group 1 received Tadenan orally at 100 mg/kg/day for 3 weeks; each rabbit in group 2 received vehicle (peanut oil). After 3 weeks of treatment (5 weeks after partial outlet obstruction), rabbits were anesthetized and cystometries were performed. Immediately after cystometry, the rabbits were euthanized, the bladder rapidly removed, and 4 longitudinal strips prepared and mounted in individual baths for contractile studies. The contractile responses to field stimulation, carbachol, adenosine-5'-triphosphate (ATP), and potassium chloride (KCl) were determined, as follows: (1) Bladder mass approximately doubled in the mildly obstructed groups. Bladder mass increased significantly (3-5-fold) in the severely obstructed groups. (2) Cystometrograms from the mildly obstructed rabbits treated with peanut oil showed low compliance, whereas those of the mildly obstructed rabbits treated with Tadenan showed normal compliance. The cystometrograms of all severely obstructed rabbits showed low compliance. (3) Mild obstruction caused small but significant decreases in the contractile response to field stimulation that were reversed by Tadenan treatment. No changes were noted in response to bethanechol, ATP, and KCl stimulation. (4) Severe obstruction caused significant decreases in the response of bladder strips to field stimulation and bethanechol. Following Tadenan therapy, there was a significant improvement in the response to high-frequency field stimulation and a substantial improvement in the response to bethanechol (response equal to control). No changes were noted in response to ATP and KCl stimulation. In conclusion, Tadenan treatment reversed the bladder dysfunctions induced by mild partial outlet obstruction, and resulted in improved bladder function in the severe model of outlet obstruction. These studies are consistent with previous studies showing that Tadenan pretreatment protects the bladder against the development of contractile dysfunctions.

Similar to all smooth muscle, contraction of urinary bladder smooth muscle depends upon a rise in intracellular free calcium, which results from both calcium influx from extracellular spaces and calcium release from intracellular stores (calcium-induced calcium release [CICR]). Recent studies from our laboratory demonstrate that one of the major dysfunctions induced by partial outlet obstruction is a marked reduction in the participation of CICR (from IP3-sensitive and IP3-insensitive sites on the sarcoplasmic reticulum [SR]) during stimulation by both field stimulation (neurotransmitter release) and by direct muscarinic stimulation (bethanechol). Experimentally, rabbit urinary bladder function can be evaluated using an isolated whole bladder model. The current study utilizes the isolated whole bladder model to compare the effects of partial outlet obstruction on the responses to field stimulation and bethanechol with the responses of normal bladders following inhibition of CICR with the combination of thapsigargin+ryanodine. The parameters measured include the magnitude of pressure generation, rate of pressure generation, time to maximal pressure generation, percent volume emptied, rate of emptying, power generation, and work performed (both total work and work per ml emptied). Partial outlet obstruction resulted in virtually identical alterations in the responses of the bladder to stimulation (field stimulation and bethanechol) to that of inhibition of CICR by thapsigargin+ryanodine. Thus, these studies provide strong support for our hypothesis that the contractile dysfunctions secondary to partial outlet obstruction are directly related to a marked inhibition of the CICR component of the response to both field stimulation and bethanechol.

Purpose: To correlate pharmacologic changes that occur in the bladder after a partial outlet obstruction with the bladder's ability to perform work and empty., Methods: After 2 weeks of partial outlet obstruction, rabbit bladders were stimulated in vitro both isovolumetrically [field stimulation (FS)] and to empty (FS, bethanechol, and KCl)., Results: The obstructed bladders were separated into two groups according to their ability to empty when stimulated with FS. Compensated bladders were those that could empty as much as controls. Decompensated bladders emptied significantly less than controls. With FS and bethanechol, the compensated obstructed bladders showed no difference from the control bladders in their ability to empty. In contrast, with KCl, the compensated bladders generated significantly less pressure, performed less work, and emptied less than controls. When the decompensated bladders were stimulated with all three types of stimulation, all parameters, including emptying ability, were significantly decreased., Conclusions: The reduction in the response of compensated bladders to KCl stimulation suggested that the initial defects to the bladder after an outlet obstruction involved the interaction of smooth muscle proteins with calcium and ATP. In contrast, the response of decompensated bladders to all three forms of stimulation was equally reduced, suggesting that the degenerative processes were directly related to significant cellular damage to metabolic processes involved in energy synthesis, storage, and utilization.

A human urinary bladder cDNA library was screened with a rat P2x purinoceptor probe. A full-length cDNA was isolated, and like its rat homologue, the deduced protein consists of 399 amino acids (M(r) = 44980 Da), contains two hydrophobic, putative transmembrane, domains flanking a large presumed extracellular loop, and represents the P2x1 subtype of this multigene family (approximately 89% amino acid sequence identity to rat P2x1, but only 40-50% identity to rat P2x2-4). Expression of the P2x1 gene in human bladder was confirmed by Northern analysis, which demonstrated a major transcript of approximately 2.9 kb. Transcripts were also found in a variety of other tissues including adult peripheral leukocytes, pancreas, spleen, prostate, small intestine, colon, testis, and ovary, and in fetal liver. The gene encoding the human P2x1 receptor was localized to chromosome 17 by Southern analysis of DNAs isolated from a panel of somatic cell hybrids. The results support a role for P2x purinoceptors in the regulation of human bladder function.

The urinary bladder requires an adequate energy supply to maintain contractile function. The primary metabolic fuel is glucose. Through glycolysis and oxidative phosphorylation, high energy phosphates are generated, which in turn supply the metabolic energy for the contractile activities of the urinary bladder. The aim of this study was to determine the effects of glucose deprivation and recovery from glucose deprivation on the phasic and tonic components of the contractile responses of rabbit bladder strips to field stimulation, bethanechol, and KCl. The results can be summarized as follow: In response to glucose deprivation, (1) the tonic responses to field stimulation, bethanechol, and KCl all decreased at a significantly greater rate than the phasic responses; (2) the phasic and tonic responses to field stimulation were both reduced to less than 10% of control within 70 minutes of initiating glucose deprivation; (3) the tonic responses to bethanechol and KCI were reduced to approximately 10% of control within 180 minutes whereas the phasic responses remained stable at 40 and 30%, respectively; and (4) glucose replacement stimulated a rapid and nearly complete recovery of the phasic and tonic components of the responses to field stimulation, bethanechol, and KCI. These results indicate that the tonic responses to all forms of stimulation are more sensitive to glucose deprivation than the phasic responses.

Partial outlet obstruction has been shown to result in contractile and metabolic dysfunctions. Specifically, there is a greater reduction in the response to field stimulation (FS) in comparison with the responses to bethanechol and KCl, a greater reduction in the tonic response to stimulation in comparison with the phasic response, and a reduction in oxidative metabolism of glucose accompanied by an increase in the glycolytic metabolism of glucose. The specific aim of the current study was to correlate the effects of partial outlet obstruction on the contractile responses of isolated strips of bladder smooth muscle to repetitive stimulation in the presence and absence of glucose. Adult male Sprague-Dawley rats were subjected to partial outlet obstruction by the surgical placement of silk ligatures around the urethra. After 2 weeks, each rate was anesthetized, the bladder was excised, and isolated strip studies were performed. These studies demonstrated that the maximal phasic response to FS was significantly decreased in the obstructed strips as compared with controls, with no difference being noted for responses to bethanechol or KCl; the tonic responses to all forms of stimulation were significantly decreased after obstruction, with the tonic response to FS being decreased to a greater degree than were the tonic responses to bethanechol and KCl; and in the absence of glucose, the tonic responses of control strips to all forms of stimulation were reduced to a greater degree than were the phasic responses. These studies demonstrate that the tonic response to FS is extremely sensitive to fatigue induced by repetitive stimulation.

1. We investigated the influence of strip length and dorsal or ventral location of rat urinary bladder strips on contractile responsiveness. 2. No differences occurred in the contractile responses of 0.5, 1.0 and 2.0 cm strips to field stimulation, carbachol, ATP, substance P or to KCl when the data were expressed as either absolute tension or as tension per cross-sectional area. However, correction for strip mass resulted in significant decreases in the contractile responses of the 2.0-cm strips compared with the 0.5-cm strips. 3. No differences occurred in length-tension curves for ventral and dorsal bladder strips, even though the strips from the dorsal surface appeared thinner than those from the ventral surface. 4. Strips from the ventral surface exhibited more variability in response to field stimulation and were less sensitive to atropine pre-treatment than were those from the dorsal surface. They were also less sensitive to the contractile effects of carbachol than dorsal strips. Dorsal and ventral strips were equally responsive to ATP, substance P and KCl. 5. Our data indicate that the contractile responsiveness of rat urinary bladder strips is independent of strip length. Although there are some differences between the cholinergic responsiveness of strips from the ventral and dorsal surfaces of the bladder, the differences are so small that for most studies they will probably have no influence on data interpretation.

1. Muscarinic receptors mediating contraction of the rat urinary bladder were characterized functionally in vitro by use of atropine, 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP methiodide), 4-diphenylacetoxy-N-(2-chloroethyl)-piperidine hydrochloride (4-DAMP mustard), hexahydro-sila-diphenidol hydrochloride (HHSiD), the p-fluoro analogue of hexahydro-sila-diphenidol hydrochloride (p-F-HHSiD), methoctramine, and pirenzepine. 2. (+)-cis-Dioxolane contracted bladder strips in a concentration-dependent manner with an EC50 of 0.169 +/- 0.018 microM and an Emax of 7.84 +/- 0.67 g. 3. Concentration-effect curves to (+)-cis-dioxolane were shifted to the right in the presence of the antagonists in a concentration-dependent manner. The rank order of antagonist affinities against the (+)-cis-dioxolane response was (pA2 values in the parentheses) atropine (9.28) > or = 4-DAMP methiodide (9.04) > HHSiD (8.01) > p-F-HHSiD (7.28) = pirenzepine (7.12) > or = methoctramine (6.77, 7.25). The profile resembles that associated with the M3 receptor subtype. 4. Atropine, 4-DAMP methiodide, pirenzepine, and methoctramine had no effects on the contractile response to 120 mM KCl. However, HHSiD and p-F-HHSiD decreased the response to KCl, and 4-DAMP mustard increased it. 5. Contractile responses to electrical field stimulation (1-32 Hz, 0.05 ms pulse duration) were biphasic in nature. The tonic response was suppressed more than the phasic response by all antagonists except methoctramine. The suppression was not always concentration-dependent, and did not seem to be related to antagonism of any one receptor subtype. 6. Our findings are consistent with the minority M3 receptors mediating the contractile response to muscarinic stimulation by (+)-cis-dioxolane in the rat bladder.

Purpose: The present studies were designed to determine the effects of in vivo and in vitro administration of ICI 198,615 (ICI), a leukotriene receptor antagonist, on the inflammatory changes that occur in the bladder after sensitization with ovalbumin., Materials and Methods: The effect of intravenous administration of ICI on urodynamic changes after instillation of ovalbumin to sensitized guinea pigs was evaluated by in vivo cystometry. Responses of in vitro bladder muscle strips to contractile stimuli and ovalbumin were also evaluated in the presence of ICI., Results: In sensitized guinea pigs, in vivo cystometry with ovalbumin induced a marked decrease in bladder capacity and increase in intravesical pressure. Pretreatment with ICI prior to cystometry prevented the ovalbumin-induced changes in capacity and intravesical pressure. There were no significant differences between control and sensitized animals in the responses of in vitro bladder muscle strips to field stimulation or bethanechol. However, maximal contractile responses to ovalbumin were significantly greater in the strips from sensitized animals than in controls. Preincubation with ICI, indomethacin, or pyrilamine alone was unable to inhibit the contractile responses to ovalbumin. However, combined administration of ICI, indomethacin and pyrilamine completely blocked the responses., Conclusions: In vivo administration of the leukotriene receptor antagonist ICI 198,615 reversed the urodynamic changes induced by ovalbumin challenge in sensitized guinea pigs. These results indicate that leukotrienes are primarily responsible for the changes in in vivo bladder function associated with sensitization.

Studies were done to compare the acute effects of streptozotocin-induced diabetes and sucrose consumption on micturition, bladder mass and contractile responses of bladder strips to field stimulation and contractile agonists. Micturition changes occurred gradually in diabetic rats, reached maximal values within 7 to 14 days, and were accompanied by significant increases in bladder mass after 7 days. Bladder strips from diabetics responded to field stimulation, carbachol and KCl with significantly greater contractions than did those from controls within 7 days. Sucrose-drinking rats had maximal increases in fluid consumption and micturition frequency on the first night after starting treatment. Increases in micturition volumes were slower to develop than in diabetics. Bladder mass was significantly increased 30 and 60 days after starting sucrose treatment. Bladder strips from sucrose-drinking rats responded to field stimulation and carbachol with significantly greater contractions than did those from controls only after 60 days. Monitoring of drinking and micturition patterns established that diabetic rats drink and urinate during both the dark and light cycles. In contrast, control and sucrose-drinking rats drink and urinate principally at night. The results demonstrate that differences in bladder function between diabetic and sucrose drinking rats are apparent during the first month after treatment begins. The data suggest that the effects of diabetes and sucrose consumption on contractile bladder function are related to the diuresis-induced increases in bladder mass.

Bladder strips from sensitized guinea pigs respond to ovalbumin challenge with a contraction accompanied by release of histamine, prostaglandin, and leukotriene. Histamine and prostaglandin release occurs preferentially from the bladder mucosa, while leukotrienes are released by the smooth muscle. This study investigated the effects of removal of the bladder mucosa on contractile responses of strips from control and sensitized guinea pigs to electrical stimulation and to contractile agonists. Removal of the mucosa potentiated the contractile response to electrical stimulation at low voltages and pulse durations. The presence of ovalbumin had no effects on the response to electrical stimulation. Removal of the mucosa had no effect on the contractile responses of bladder strips to bethanechol, histamine, KCl, or ovalbumin, although after correction for the decreased strip mass after mucosa removal there was a tendency for the responses to increase. We conclude that the responsiveness of bladder strips from sensitized guinea pigs to ovalbumin challenge results primarily from effects which occur within the smooth muscle.

Micturition can be characterized experimentally by monitoring both the frequency and volume of micturition. Previous studies demonstrated that the functional capacity of the rat and rabbit bladder, as determined by cystometry, is approximately equal to the maximal single micturition volume as recorded over a 24 hour period. Studies in many laboratories have demonstrated that chronic increases in diuresis induce increases in micturition frequency and capacity, and an increase in bladder mass. The current study compares the temporal relationship among these parameters in three models of diuresis: streptozotocin-induced diabetes in rats, sucrose-induced diuresis in rats, and furosemide-induced diuresis in rabbits. In both sucrose diuresis in rats and furosemide diuresis in rabbits there were immediate increases in both the frequency and volume of micturition. The magnitude of the increases in micturition frequency and micturition volume paralleled the increase in the total volume of urine excreted. Bladder mass increased progressively over the time course of the study. Streptozotocin-induced diabetes resulted in a more gradual (but parallel) increase in micturition frequency and volume, and again a more gradual increase in bladder mass. These studies demonstrate that functional bladder capacity is increased immediately upon the initiation of diuresis with sucrose or furosemide, as is the frequency of micturition. This indicates that functional bladder capacity is probably under neuronal regulation and the change in capacity is not a function of the increased bladder mass which occurs at a later time period.(ABSTRACT TRUNCATED AT 250 WORDS)

1. The responses of bladder strips from control, streptozotocin-diabetic, and sucrose-drinking rats to electrical field stimulation were investigated. Sucrose-drinking rats were included as additional controls because they have enlarged bladders as a result of non-diabetic diuresis. 2. Bladder strips from diabetic rats developed more spontaneous activity than those from the two control groups. Indomethacin reduced the amplitude and frequency of spontaneous contractions suggesting that they resulted from endogenous prostaglandin formation. Tetrodotoxin (TTX) had little effect, while alpha, beta-methylene ATP caused increases in spontaneous activity. 3. Bladder strips from diabetic rats responded to field stimulation with greater contractions than controls in the absence of antagonists as well as in the presence of atropine and alpha, beta-methylene ATP. Increasing TTX concentrations caused a step-wise depression of the contractile response to electrical stimulation which was not affected by preincubation with either atropine or alpha, beta-methylene ATP. 4. Atropine and indomethacin had no effect on strength-duration curves constructed to measure threshold contractile responses to five pulses stimulation. The curves were shifted to the right by both TTX and alpha, beta-methylene ATP, indicating that the responses were neurogenic in nature and at least partially, the result of stimulation of P2-purinoceptors. In the absence of drugs, bladder strips from diabetics responded at lower voltages and pulse widths than those of control and sucrose-drinking rats, suggesting that they were more excitable. 5. The response curve of bladder strips from diabetics to field stimulation at increasing voltage was shifted upwards and to the left compared to strips from control or sucrose-drinking rats. 6. Bladder strips from diabetics responded to stimulation at increasing pulse width with greater responses than those from control or sucrose-drinking rats. At 1.0 ms pulse width, the TTX-resistant response of strips from diabetic rats was still greater than that of the other groups, indicating that a myogenic component was also involved.7. The data suggest that bladder strips from diabetic rats are more excitable than those of control or sucrose-drinking rats. This may result from diabetes-induced decreases in bladder lipid or other membrane changes, and/or be a result of partial depolarization, perhaps related to diabetic neuropathy.

1. Partial outflow obstruction induces marked changes in detrusor contractile function and morphology. One common finding in all experimental animal models of partial outflow obstruction is a significant increase in bladder mass. 2. Previous studies have demonstrated that partial outlet obstruction induces a rapid and substantial increase in [3H]thymidine incorporation into virtually all cellular elements of the bladder. 3. The present study was designed to investigate the [3H]thymidine uptake and localization induced by exposure of the in vitro whole rat bladder model to various intravesical pressures and rates of intravesical infusion. 4. The results are as follows: (a) There were no differences in DNA concentration between control and other groups. (b) Slow infusion induced a mild increase in DNA synthesis ([3H]thymidine incorporation) at 0.5 ml and a significantly greater level of DNA synthesis at 1.6 ml. (c) [3H]thymidine incorporation was significantly increased by exposure to 7.5 cm H2O, 15 cm H2O, and 30 cm H2O. (d) Exposure to 60 cm H2O and 90 cm H2O did not initiate an increase in [3H]thymidine incorporation. (e) Autoradiography showed that all tissue elements (urothelium, connective tissue, smooth muscle) participated in the response.

The modulation of urinary bladder function by sex hormones was examined in castrated and sham-operated male and female streptozotocin-diabetic rats. Male and female diabetic rats weighed less than age-matched controls and had significantly greater serum glucose levels and bladder weights. Castration had no effect on bladder mass and did not alter the diabetes-induced changes in rat or bladder mass. Protein concentrations were significantly increased and collagen concentrations were significantly decreased in bladders from diabetic rats compared with non-diabetics. Sex or castration had no effects on protein or collagen concentration of bladders from nondiabetic and diabetic rats. There were no differences in water consumption and urine excretion between male and female nondiabetic rats, and no effects of castration were observed on micturition in nondiabetic rats. Ovariectomy followed by diabetes caused a significant increase in urine excretion compared with diabetes alone. Ovariectomized diabetic rats had increased mean and maximal micturition volumes when compared with other female rats. Orchiectomy had no effects on the expected increases in micturition associated with diabetes. Diabetes in male rats caused significant increases in contractile responses of bladder strips to field stimulation, carbachol, KCl and high concentrations of ATP. In both nondiabetic and diabetic groups, orchiectomy had no effects on the contractile responses compared with sham operation. Similarly, in bladder strips from diabetic females, contractile responses to carbachol, KCl and high concentrations of ATP were significantly increased compared with those of nondiabetics, and were unchanged by ovariectomy. However, ovariectomy in nondiabetic rats caused significant decreases in contractile responsiveness to nerve stimulation, effects which were only partially prevented by diabetes. The data suggest that there are few differences between male and female rats in their sensitivity to streptozotocin and the effects of diabetes on micturition, bladder collagen and protein concentration, and the responsiveness of bladder strips to contractile agents. The changes in bladder function observed after induction of diabetes do not appear to be related to changes in sex hormone levels. The major differences noted between males and females were the decreased responsiveness of bladders from nondiabetic ovariectomized female rats to field stimulation. In conjunction with previous data obtained in this laboratory, the study suggests that the responses to field stimulation are more sensitive to the effects of ovariectomy than are the responses to contractile agonists.

In a preliminary study we showed that 14 days of furosemide infusion in rabbits caused increases in bladder mass and contractile responses of bladder body strips to field stimulation, bethanechol, ATP and KCl. The present study investigated the temporal effects of furosemide-induced diuresis on micturition, bladder mass, bladder wall proliferation activity and DNA synthesis. In addition, contractile responses of bladder body strips were monitored. Furosemide-containing osmotic pumps were implanted in male New Zealand White rabbits. Micturition was monitored for 7 days. Biochemical analyses were done 3, 7 and 14 days after implantation. Contractile responses were measured at 3 and 7 days. Polyuria and polydipsia started within 1 day after implantation of furosemide-containing osmotic pumps and continued at the same level for 7 days. Bladder mass was significantly increased at 3 and 7 days. Diuresis stimulated 3H-thymidine uptake and caused an increase in bladder DNA concentration at 3 days. However, both DNA concentrations and 3H-thymidine levels returned to control levels by 7 days. Contractile responses to field stimulation and agonists were increased at 7 days but unchanged at 3 days. The data confirm that modest increases in bladder mass and the ensuing increases in contractile function are a normal and beneficial physiological response to diuresis.

In vivo and in vitro bladder function were studied in three different models of increased diuresis: 1) Brattleboro rats with hereditary diabetes insipidus (di/di), 2) Sprague-Dawley rats with streptozotocin-induced diabetes mellitus (STZ), and 3) Sprague-Dawley rats with increased diuresis due to 5% sucrose added to the drinking water. When compared with controls, all three models showed bladder mass, increased water consumption and urine output, higher mean and maximal increased micturition volumes, and greater bladder capacity and compliance by in vitro cystometry. The changes were more extensive in di/di rats than in the STZ and sucrose-drinking rats. The concentration of bladder collagen decreased in all three rat models when compared with controls. However, the collagen concentration of STZ bladders was significantly lower than the collagen concentration of di/di and sucrose bladders, suggesting that the decrease in bladder collagen concentration associated with experimental diabetes mellitus is only partly related to the increased diuresis. Contractile function was studied using a whole bladder model. Responses of whole bladders from control and diabetic rats to electrical field stimulation, carbachol and KCl were identical. Volume-pressure relations of the isolated whole bladder showed that the magnitude of the contractile response to KCl is constant at intravesical volumes ranging from about 10 to 95% of cytometrical bladder capacity. Bladders from Brattleboro di/di rats and STZ rats showed a rightward shift of volume-passive pressure curves when compared with appropriate controls. Bladders from sucrose-drinking rats had volume-passive pressure curves similar to the bladders from controls. This study suggests that while contractile function remains intact with increased diuresis, the passive function changes, with the bladder becoming more distensible.