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Purpose: We examined the effects of intravenous administration of the 2 nuclear factor-kappaB inhibitors aspirin and 2-hydroxy-4-trifluoromethylbenzoic acid (HTB) on bladder filling and voiding in anesthetized and conscious rats., Materials and Methods: Disappearance of isovolumic bladder contractions after intravenous administration of different doses of aspirin and HTB in anesthetized, transurethrally catheterized rats was evaluated. Cystometry was performed in conscious rats during bladder infusion with saline or diluted acetic acid as well as in those with cyclophosphamide induced cystitis. Changes in bladder capacity and voiding pressure were evaluated after intravenous administration of test compounds., Results: Aspirin induced a dose dependent disappearance of isovolumic bladder contractions in anesthetized rats with an extrapolated dose of 2.1 mg./kg. inducing 10 minutes of bladder quiescence. HTB was practically inactive, inducing a dose independent block of 3 to 4 minutes after intravenous administration of 1 to 10 mg./kg. In conscious rats with a bladder infused with saline aspirin was poorly active on bladder capacity, inducing a 20% increase 60 minutes after intravenous administration of 30 and 100 mg./kg. In rats with a bladder infused with acetic acid aspirin was much more active when injected at the initiation of inflammation and after 1 hour of irritant infusion. In this latter situation aspirin increased bladder capacity up to 60% after intravenous administration of 30 and 100 mg./kg. Similar results were obtained in rats with cyclophosphamide induced cystitis in which the bladder was infused with saline. In these cystometrography models 30 mg./kg. HTB intravenously was completely inactive., Conclusions: The results show that HTB is devoid of significant effects on the micturition reflex in the absence or presence of bladder inflammation, suggesting that acute inhibition of nuclear factor-kappaB does not influence bladder urodynamics in rats. In contrast, aspirin, which is a cyclooxygenase and nuclear factor-kappaB inhibitor, was always effective, indicating the important role of cyclooxygenase enzymes.

Several novel N-arylpiperazine derivatives were synthesized and tested for their 1) affinity and functional activity on 5-hydroxytryptamine(1A) (5-HT(1A)) receptors in vitro; 2) activity in models predictive of antagonism at somatodendritic and postsynaptic 5-HT(1A) receptors; and 3) effects on the micturition reflex in anesthetized and conscious rats. These studies also included 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide (NAN 190), 8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4, 5]decane-7,9-dione dihydrochloride (BMY 7378), and N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl-N-(2-pyridinyl)cyclohex anecarboxamide (WAY 100635). Almost all compounds were found to be potent and selective for the human recombinant 5-HT(1A) receptor, with K(i) values in the nanomolar range. [(35)S]GTPgammaS binding in HeLa cells expressing the recombinant human 5-HT(1A) receptor allowed classification of the compounds into neutral antagonists and partial agonists. Almost all neutral antagonists were active in blocking 8-hydroxy-2-dipropylaminotetralin (8-OH-DPAT)-induced forepaw treading in rats (postsynaptic model) and hypothermia in mice (somatodendritic model) with the same potency, whereas compounds showing partial agonistic activity were active in the postsynaptic model but were inactive, or poorly active, in the somatodendritic model. Neutral antagonists potently inhibited volume-induced bladder-voiding contractions in anesthetized rats. Contractions were completely blocked, and the disappearance of bladder contractions lasted 7 to 13 min after the highest doses tested. Furthermore, neutral antagonists increased bladder volume capacity in conscious rats during continuous transvesical cystometry, whereas micturition pressure was only slightly, and not dose-dependently, reduced. Partial agonists were inactive or poorly active, inducing a disappearance time of bladder contractions that did not exceed 6 min in anesthetized rats, and failing to increase bladder volume capacity in conscious rats. These findings indicate that only neutral 5-HT(1A) receptor antagonists are endowed with inhibitory effects on the bladder.

The present studies were undertaken to examine the in vitro calcium antagonistic properties of lercanidipine (CAS 132866-11-6, Rec 15/2375) in vascular and non-vascular tissues, as well as its binding profile and in particular its affinity to the calcium channel binding sites. Lercanidipine proved to be endowed with high affinity for the dihydropyridine subunit of the L-type calcium channel, where it was much more potent than on the other receptors tested. The nature of the interaction of lercanidipine with the calcium channel appears competitive, as evidenced by a progressive increase in the apparent Kd of the ligand with no change in Bmax. The performed functional in vitro studies in isolated vascular and cardiac tissues demonstrated that lercanidipine has a slower onset and offset of calcium antagonistic activity compared with other calcium antagonists. The time-course of inhibition of vascular smooth muscle contraction showed substantial differences after addition of lercanidipine with regard to the other calcium antagonists tested (nitrendipine and amlodipine). On repeated washing of rat aorta to remove the drugs from the preparation, the effects of nitrendipine disappeared rapidly. After amlodipine incubation, contractility of the tissue was still impaired after 6 h washout with the highest concentrations tested, but completely recovered in 1-3 h after washout of the lowest concentration. On the contrary, the preparations incubated with lercanidipine showed a decrease in contractility that reached the maximum 1 to 3 h after the removal of the compound from the bath at all the active concentrations tested. The functional calcium antagonistic activity of lercanidipine was also evaluated as relaxing potency against the tonic contractions induced by preincubation of rat aorta, bladder and colon with 80 mmol/l K+. In rat aorta, lercanidipine proved more potent than nitrendipine. Comparing the IC50 values evaluated after 3 h of contact time, lercanidipine resulted more active on the vascular tissue with potency ratios of 177 and 8.5 for aorta vs bladder and aorta vs colon, respectively. In contrast, nitrendipine showed about the same activity in the three tested tissues, and potency ratios of 2.0 and 0.8 for aorta vs bladder and aorta vs colon were calculated. In rat aortic strips maintained during the incubation with lercanidipine at different degrees of depolarization, the functional calcium antagonistic activity markedly increased by raising the tissue depolarization and the potency ratio between the IC50 values evaluated at 5 and 100 mmol/l K+ resulted 138. Nitrendipine provided very similar results, whereas nifedipine activity did not seem to be affected by raising the tissue depolarization. The negative inotropic effects of lercanidipine on normally and partially depolarized rabbit ventricular strips, as well as in guinea-pig atria, were negligible in comparison to its effects on vasculature. On the whole these characteristics suggest a slow onset of action and long duration of effects also after in vivo administration. In addition, the unique vascular selectivity of lercanidipine implies that the therapeutically desirable vasodilator activity is not or scarcely associated with a decrease in cardiac contractile force.

The antispasmodic activity of terflavoxate (CAS 86433-39-8), a flavone derivative with spasmolytic properties on the urinary tract, has been studied in vitro, in comparison to the most common drugs utilized in the therapy of overactive detrusor, namely flavoxate, oxybutynin, and terodiline. Terflavoxate showed affinity for bladder (and brain) muscarinic receptors at micromolar level, however, its activity on carbachol-induced contractions of rat bladder was clearly non competitive, indicating that the compound is devoid of functional antimuscarinic property. Moreover, the observation that unlike antimuscarinic drugs, terflavoxate inhibited by more than 50% field stimulation-induced contractions of rabbit bladder strips, indicates that mechanisms other than the anticholinergic one should be responsible for its smooth muscle relaxant properties. Terflavoxate, flavoxate, oxybutynin, and terodiline were equally effective in inhibiting the two components of K(+)-induced contractions, while nifedipine and nicardipine were more potent than the other compounds, and more effective in inhibiting tonic than phasic contractions. In addition, while nifedipine and nicardipine antagonized in a competitive manner calcium-induced contractions of potassium-depolarized bladder strips, the other spasmolytics behaved as mixed antagonists. Differences in calcium antagonistic properties between nifedipine and nicardipine on one side, and terflavoxate on the other, are further demonstrated by the data on binding experiments. Nevertheless, present results suggest that Ca(++)-antagonistic effects are mainly responsible for terflavoxate smooth muscle relaxant properties.

The model originally proposed by Postius and Szelenyi for in vivo screening of spasmolytic compounds on the rat urinary bladder, has been modified and tested to verify its predictivity. The topically applied KCl induced reproducible contractions of the bladder that were dose dependently inhibited by i.v. administration of calcium antagonists like nifedipine, nicardipine, and verapamil. The other spasmolytics tested (oxybutynin, terodiline, flavoxate, and papaverine), showed a non-dose-related inhibition of the contractions. The in vivo potency of the calcium antagonists was related to their in vitro activity on the agonist-induced contractions of rat bladder strips, whereas the activity of the other spasmolytics appeared higher than that predicted on the basis of their in vitro efficacy. Nicardipine showed a dose-dependent inhibition of KCl-induced contractions also after oral administration, whereas oxybutynin and papaverine behaved as after i.v. administration. The described model represents, therefore, a good, quantitative, and reproducible tool of screening at the bladder level only for antispasmodic drugs endowed with strong calcium antagonistic activity.

The influence of the oral administration of different doses of citalopram (5, 15 and 45 mg/kg), imipramine (15, 30, 45 and 60 mg/kg), nortriptyline (15, 45 and 60 mg/kg) and amineptine (45 mg/kg) on stress-induced analgesia has been studied in anaesthetized rats. None of the administered antidepressants seem to have appreciable analgesic activity when analgesia is tested by the tail-immersion method. Citalopram, imipramine and nortriptyline, but not amineptine, increase the analgesia induced by inescapable footshock delivered continuously for 2 min to rats. Citalopram is the most potent drug. Our results support the suggested importance of 5-HT and noradrenaline terminals, but not those of dopamine, in the mediation of the stress-induced analgesia and seem to support the hypothesis that the analgesic activity of antidepressants is partially related to their modulating effects on the endogenously released opioid peptides involved in the endogenous pain inhibitory systems.

Seizures, neuronal damage and extracellular Ca2+ concentration were studied in rats unilaterally injected in the dorsal hippocampus with quinolinic acid, a brain metabolite with excitotoxic properties. In freely moving animals, in the first 2 h after the injection of a convulsant and neurotoxic dose (156 nmol), quinolinic acid induced a tetrodotoxin-insensitive decrease in the extracellular Ca2+ concentration (nadir 40%) in the injected area, as assessed by brain dialysis coupled to a fluorimetric method for Ca2+ detection. Blockade of quinolinic acid-induced decrements in Ca2+ by 15.6 nmol D-(-)2-amino-7-phosphonoheptanoic acid indicated that this effect was receptor-mediated. Dose-response relationships showed a close association between seizure activity (measured by EEG) and extracellular Ca2+ changes in the injected area. Changes in Ca2+ were apparent at the site of injection prior to the onset of focal seizures and they were not found in the homotypic structure where seizures were conducted. Drugs effective in blocking seizures (carbamazepine and flunarizine) prevented the fall in extracellular Ca2+, while drugs without anticonvulsant activity (ethosuximide and nifedipine) did not. Destruction of nerve cells by quinolinic acid was not prevented by treatment with carbamazepine and flunarizine. The results suggest that the fall in extracellular Ca2+ observed in the first 2 h after quinolinic acid, probably reflecting the ion influx into neurons, is involved in triggering focal seizures but is not related to the occurrence of nerve cell death.