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Angiopoietin-related growth factor (AGF), a novel hepatokine, showed therapeutic implications in diabetic and obese animal models. Although the physiologic functions of human AGF have not yet been identified, serum levels of AGF displayed up-regulation in groups with diseases including preeclampsia and diabetes; and there was little association between genetic variability of AGF and metabolic syndrome–related phenotypes. We analyzed serum levels of AGF and other biochemical and anthropometric markers in 216 Korean persons—the numbers of healthy controls and those with metabolic syndrome were 138 and 78, respectively—to confirm research data from animal models. Women had higher AGF than men (265.01 vs 311.84 ng/mL, P = .003). This study showed that serum AGF levels were significantly higher in subjects with metabolic syndrome (325.89 ng/mL) than those in the healthy group (272.44 ng/mL) ( P = .003). Among the components of metabolic syndrome, subjects with high waist circumference or decreased high-density lipoprotein cholesterol had significantly increased serum AGF (271.92 vs 313.68 ng/mL, P = .013; 271.01 vs 310.58 ng/mL, P = .023, respectively). According to multivariate regression analysis, metabolic syndrome itself and waist circumference could be used, in addition to sex and age, as predictors of serum AGF level. In conclusion, serum AGF levels were paradoxically increased in metabolic syndrome, in comparison with data from animal experiments and data on sex, age, and waist circumference. Metabolic syndrome can be a predictor of serum AGF level. Further studies are needed to explore the possibilities of compensatory up-regulation, or AGF resistance, to explain the physiologic roles of AGF in metabolic syndrome.

Aims To investigate associations between γ-glutamyltransferase (GGT) and components of metabolic syndrome (MS), insulin resistance and inflammatory markers in the Korean population. Methods The 3508 subjects enrolled in this survey participated in the Korean Rural Genomic Cohort (KRGC) study. Written consent was obtained from the local ethical committee. Of these participants, 1437 were men (mean age 56.9 ± 7.9 years) and 2071 were women (mean age 55.8 ± 8.1 years). We measured GGT levels and various biochemical markers. To examine insulin resistance status, we used the homeostasis assessment method for insulin resistance (HOMA-IR). For inflammatory marker, we used C-reactive protein (CRP) levels. Results Serum GGT levels were significantly higher in the MS group compared to the healthy patient group [23 (5–1403) vs. 19 (5–1920) IU/l; P = 0.01]. The prevalence of MS and adjusted relative risk were both significantly increased from the lowest to highest GGT quartiles; these results persisted after adjustments for multiple confounders. Positive correlations were established between GGT and HOMA-IR or CRP. Conclusion These results suggest that GGT levels may be a surrogate marker of insulin resistance, inflammation and MS.

Activation of muscarinic acetylcholine receptors (mAChR) is one of the most important signal transduction pathways in the human body. In this study, we investigated the role of mAChR activation in relation to its subtypes in human retinoblastoma cell-lines (WERI-Rb-1) using Ca2+ measurement, real-time PCR, and Western Blot techniques. Acetylcholine (ACh) produced prominent [Ca2+]i transients in a repeated manner in WERI-Rb-1 cells. The maximal amplitude of the [Ca2+]i transient was almost completely suppressed by 97.3 ± 0.8% after atropine (1 µM) pretreatment. Similar suppressions were noted after pretreatments with thapsigargin (1 µM), an ER Ca2+-ATPase (SERCA) inhibitor, whereas the ACh-induced [Ca2+]i transient was not affected even in the absence of extracellular calcium. U-73122 (1 µM), a PLC inhibitor, and xestospongin C (2 µM), an IP3-receptor antagonist, elicited 11.5 ± 2.9% and 17.8 ± 1.9% suppressions, respectively. The 50% inhibitory concentration of (IC50) values for blockade of a 100 µM ACh response by pirenzepine and 4-DAMP were 315.8 and 9.1 nM, respectively. Moreover, both M3 and M5 mAChRs were prominent in quantitative real-time-PCR. Taken together, the M3/M5 subtypes appear to be the major contributor, leading to intracellular calcium mobilization from the internal store via an IP3-dependent pathway in the undifferentiated retinoblastoma cells. Keywords:: muscarinic receptor, calcium, retinoblastoma

Functional gastrointestinal disorders (FGID) affect millions of people spread all age regardless of race and sex. Emotional stress and obesity have been associated with increased reporting of gastrointestinal (GI) symptoms, but the relationship between FGID and risk factors (emotional stress or obesity) is unclear. Our aim was to assess the changes of the mechanical characteristics on the gastrointestinal tracts of the mentally fatigued obese and normal rat models. Finally, using the physical characteristics with micro-indentation test, we made a close investigation into the relation between FGID and risk factors quantitatively., {"references":["","S. Haag, ''Symptom patterns in functional dyspepsia and irritable bowel syndrome: relationship to disturbances in gastric emptying and response to a nutrient challenge in consulters and non-consulters,'' Gut, vol. 53, pp. 1445-1451, 2004.","N. J. Talley, ''Symptom patterns in functional dyspepsia and irritable bowel syndrome: relationship to disturbances in gastric emptying and response to a nutrient challenge in consulters and non-consulters,'' Am J Gastroenterol., vol. 99, pp. 1807-1814, 2004.","F. Cremonini, ''Relationship between upper gastrointestinal symptoms and changes in body weight in a population-based cohort,'' Neurogastroenterol Motil., vol. 18, pp. 987-994, 2006.","K. M. Flegal, ''Prevalence and trends in obesity among US adults,'' JAMA, vol. 288, pp. 1723-1727, 2002.","M. Nilsson, ''Obesity and estrogen as risk factors for gastroesophageal reflux symptoms,'' JAMA, vol. 290, pp. 66-72, 2003.","J. Lagergren, ''No relation between body mass and gastro-oesophageal reflux symptoms in a Swedish population based study,'' Gut, vol. 47, pp. 26-29. 2000.","M. Nilsson, ''Body mass and reflux oesophagitis: an oestrogen-dependent association?'' Scand J Gastroenterol., vol. 37, pp. 626-630, 2002.","G. R. Locke, ''Risk factors associated with symptoms of gastroesophageal reflux,'' Am J Med., vol. 106, pp. 642-649, 1999.","H. M?nnikes, ''Role of Stress in Functional Gastrointestinal Disorders Evidence for Stress-Induced Alterations in Gastrointestinal Motility and Sensitivity,'' Digestive diseases, vol. 19, no. 3, pp. 201-211, 2001.\n[10] R. L. Levy, ''Psychosocial Aspects of the Functional Gastrointestinal Disorders,'' Gastro., vol. 130, pp. 1447-1258, 2006\n[11] K. W. Min, ''Interstitial Cells of Cajal (ICC) and Gastrointestinal Stromal Tumor (GIST): facts, speculations, and myths,'' J. Cell Mol Med., vol. 10, pp. 995-1013, 2006.\n[12] M. Takaki. ''Cut pacemaker cells: the interstitial cells of cajal (ICC),'' J. Smooth Muscle Res., vol. 39, pp. 137-161, 2003.\n[13] K. D. Keef, ''Basal release of nitric oxide induces an oscillatory motor pattern in canine colon,'' J. Physiol., vol. 499, pp. 773-786, 1997.\n[14] T. K. Smith, ''Interaction of two electrical pacemakers in the muscularis of the canine proximal colon,'' Am. J. Physiol., vol. 252, pp. 290-299, 1987.\n[15] A. C. Guyton, Textbook of medical physiology. 10 ed. W.B. Saunders, Philadelphia, 2000."]}

Objective To evaluate the cardiopulmonary endurance of subjects with spinal cord injury by measuring the maximal oxygen consumption with varying degrees of spinal cord injury level, age, and regular exercise. Methods We instructed the subjects to perform exercises using arm ergometer on healthy adults at 20 years of age or older with spinal cord injury, and their maximal oxygen consumption (VO2max) was measured with a metabolic measurement system. The exercise proceeded stepwise according to the exercise protocol and was stopped when the subject was exhausted or when VO2 reached an equilibriu Results Among the 40 subjects, there were 10 subjects with cervical cord injury, 27 with thoracic cord injury, and 3 with lumbar cord injury. Twenty-five subjects who were exercised regularly showed statistically higher results of VO2max than those who did not exercise regularly. Subjects with cervical injury showed statistically lower VO2max than the subjects with thoracic or lumbar injury out of the 40 subjects with neurologic injury. In addition, higher age showed a statistically lower VO2max. Lastly, the regularly exercising paraplegic group showed higher VO2max than the non-exercising paraplegic group. Conclusion There are differences in VO2max of subjects with spinal cord injury according to the degree of neurologic injury, age, and whether the subject participates in regular exercise. We found that regular exercise increased the VO2max in individuals with spinal cord injury.

BackgroundEpstein-Barr virus (EBV) infection immortalizes primary B cells in vitro and generates lymphoblastoid cell lines (LCLs), which are used for several purposes in immunological and genetic studies. Purinergic receptors, consisting of P2X and P2Y, are activated by extracellular nucleotides in most tissues and exert various physiological effects. In B cells, especially EBV-induced LCLs, their expression and function have not been well studied. We investigated the expression of P2 receptors on primary human B cells and LCLs using the quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method for revealing the gene expression profile of the P2 receptor subtypes and their changes during transformation.ResultsThe mRNA transcripts of most P2 receptors were detected in primary B cells; the expression of P2X3and P2X7receptors was the lowest of all the P2 receptors. By contrast, LCLs expressed several dominant P2 receptors – P2X4, P2X5, and P2Y11– in amounts similar to those seen in B cells infected with EBV for 2 weeks. The amount of most P2 subtypes in LCLs or EBV-infected B cells was lower than in normal B cells. However, the amount of P2X7receptor expressed in LCLs was higher. Protein expression was studied using Western blotting to confirm the mRNA findings for P2X1, P2X4, P2X7, P2Y1, and P2Y11receptors. ATP increased the intracellular free Ca2+concentration ([Ca2+]i) by enhancing the Ca2+influx in both B cells and LCLs in a dose-dependent manner.ConclusionThese findings describe P2 receptor expression profiles and the effects of purinergic stimuli on B cells and suggest some plasticity in the expression of the P2 receptor phenotype. This may help explain the nature and effect of P2 receptors on B cells and their role in altering the characteristics of LCLs.

Several pharmacological and physiological studies have suggested that GABA(A) receptors (GABA(A) Rs) may exist in the rat major pelvic ganglion (MPG), a large coalescent pelvic ganglion that contains both sympathetic and parasympathetic components which innervates pelvic organs. However, the presence of GABA(A) R in the MPG has never been demonstrated directly by morphological studies. In the present study, we used immunohistochemistry to demonstrate the existence of GABA(A) R beta2/3 subunits for the first time in the rat MPG. We also analyzed the neurochemical properties of MPG neurons expressing GABA(A) R beta2/3 subunits. GABA(A) R beta2/3-immunoreactive (-IR) neurons occupied 27.4+/-7.0% of the whole neuronal population, and many of these (77.6%) were co-localized with tyrosine hydroxylase (TH). Likewise, most (86.5%) of TH-IR neurons were GABA(A) R beta2/3-positive. GABA(A) R beta2/3 subunits were also expressed in a few VIP- or NOS-IR neurons, the cholinergic or non-adrenergic, non-cholinergic (NANC) neurons. These results suggest that GABA(A) Rs are involved in the modulation of most sympathetic, noradrenergic neurons and also a subset of VIP and NOS neurons of the rat MPG.

1. We investigated the role of deoxycholic acid in pacemaker currents using whole-cell patch-clamp techniques at 30 degrees C in cultured interstitial cells of Cajal (ICC) from murine small intestine. 2. The treatment of ICC with deoxycholic acid resulted in a decrease in the frequency and amplitude of pacemaker currents and increases in resting outward currents. Also, under current clamping, deoxycholic acid produced the hyperpolarization of membrane potential and decreased the amplitude of the pacemaker potentials. 3. These observed effects of deoxycholic acid on pacemaker currents and pacemaker potentials were completely suppressed by glibenclamide, an ATP-sensitive K(+) channel blocker. 4. NS-398, a specific cyclooxygenase-2 (COX-2) inhibitor, significantly inhibited the deoxycholic acid-induced effects. The treatment with prostaglandin E(2) (PGE(2)) led to a decrease in the amplitude and frequency of pacemaker currents and to an increase in resting outward currents, and these observed effects of PGE(2) were blocked by glibenclamide. 5. We next examined the role of deoxycholic acid in the production of PGE(2) in ICC, and found that deoxycholic acid increased PGE(2) production through the induction of COX-2 enzyme activity and its gene expression. 6. The results suggest that deoxycholic acid inhibits the pacemaker currents of ICC by activating ATP-sensitive K(+) channels through the production of PGE(2).

We investigated whether substance P modulates pacemaker currents generated in cultured interstitial cells of Cajal of murine small intestine using whole cell patch-clamp techniques at 30 degrees C. Interstitial cells of Cajal generated spontaneous inward currents (pacemaker currents) at a holding potential of -70 mV. Tetrodotoxin, nifedipine, tetraethylammonium, 4-aminopyridine, or glibenclamide did not change the frequency and amplitude of pacemaker currents. However, divalent cations (Ni2+, Mn2+, Cd2+, and Co2+), nonselective cationic channel blockers (gadolinium and flufenamic acid), and a reduction of external Na+ from normal to 1 mM inhibited pacemaker currents indicating that nonselective cation channels are involved in their generation. Substance P depolarized the membrane potential in current clamp mode and produced tonic inward pacemaker currents with reduced frequency and amplitude in voltage clamp mode. [D-Arg1, D-Trp7,9, Leu11] substance P, a tachykinin NK1 receptor antagonist, blocked these substance P-induced responses. Furthermore, [Sar9, Met(O2)11] substance P, a specific tachykinin NK1 receptor agonist, depolarized the membrane and tonic inward currents mimicked those of substance P. Substance P continued to produce tonic inward currents in external Ca2+-free solution or in the presence of chelerythrine, a protein kinase C inhibitor. However, substance P-induced tonic inward currents were blocked by thapsigargin, a Ca2+-ATPase inhibitor in the endoplasmic reticulum or by an external 1 mM Na+ solution. Our results demonstrate that substance P may modulate intestinal motility by acting on the interstitial cells of Cajal by activating nonselective cation channels via the release of intracellular Ca2+ induced by tachykinin NK1 receptor stimulation.

Department of Chemistry, Graduate School, Yonsei University, Seoul 120-749, KoreaReceived May 8, 2002Friedel-Crafts alkylation reaction of an isomeric mixture of 1,2,3,4,5,6,7,8- (2) and 1,2,3,4,5,6,7,8-octahydrophenanthrene (2') with excess vinylchlorosilanes such as vinyl(methyl)dichlorosilane (1a) andvinyltrichlorosilane (1b) in the presence of aluminum chloride catalyst at 80

The effects of arachidonic acid (AA) and the mechanism through which it modulates ATP-sensitive K+ (KATP) currents were examined in single smooth muscle cells of murine proximal colon. In the current-clamping mode, AA and glibenclamide induced depolarization of membrane potential. Using 0.1 mM ATP and 140 mM K+ solution in the pipette and 90 mM K+ in the bath solution at a -80 mV of holding potential, pinacidil activated the glibenclamide-sensitive inward current. The potential of these currents was reversed to near the equilibrium potential of K+ by 60 mM K+ in the bath solution. AA inhibited KATP currents in a dose-dependent manner. This inhibition was not changed when 1 mM GDPβS was present in the pipette. Chelerythrine, protein kinase C inhibitor, did not block the AA effects. Superoxide dismutase and metabolic inhibitors (indomethacin and nordihydroguaiacretic acid) of AA did not affect the AA-induced inhibition. Eicosatetraynoic acid, a nonmetabolizable analogue of AA, inhibited the KATP currents. These results suggest that AA-induced inhibition of KATP currents is not mediated by G-protein or protein kinase C activation. The inhibitory action is likely to be a possible mechanism of AA-induced membrane depolarization.

We investigated the regulation of ATP-sensitive K+(KATP) currents in murine colonic myocytes with patch-clamp techniques. Pinacidil (10−5M) activated inward currents in the presence of high external K+(90 mM) at a holding potential of −80 mV in dialyzed cells. Glibenclamide (10−5M) suppressed pinacidil-activated current. Phorbol 12,13-dibutyrate (PDBu; 2 × 10−7M) inhibited pinacidil-activated current. 4-α-Phorbol ester (5 × 10−7M), an inactive form of PDBu, had no effect on pinacidil-activated current. In cell-attached patches, the open probability of KATPchannels was increased by pinacidil, and PDBu suppressed openings of KATPchannels. When cells were pretreated with chelerythrine (10−6M) or calphostin C (10−7M), inhibition of the pinacidil-activated whole cell currents by PDBu was significantly reduced. In cells studied with the perforated patch technique, PDBu also inhibited pinacidil-activated current, and this inhibition was reduced by chelerythrine (10−6M). Acetylcholine (ACh; 10−5M) inhibited pinacidil-activated currents, and preincubation of cells with calphostin C (10−7M) decreased the effect of ACh. Cells dialyzed with protein kinase C ɛ-isoform (PKCɛ) antibody had normal responses to pinacidil, but the effects of PDBu and ACh on KATPwere blocked in these cells. Immunofluorescence and Western blots showed expression of PKCɛ in intact muscles and isolated smooth muscle cells of the murine proximal colon. These data suggest that PKC regulates KATPin colonic muscle cells and that the effects of ACh on KATPare largely mediated by PKC. PKCɛ appears to be the major isozyme that regulates KATPin murine colonic myocytes.

Uridine 5'-triphosphate (UTP) is stored in the granules of cells such as platelets and is released into the extracellular space upon cell stimulation. Extracellular UTP is known to influence many biological processes. We investigated the hemodynamic effects of UTP on the perfused rat liver and characterized its receptors. Liver perfusions were performed in a recirculation system under constant pressure (28 cmH2O). The perfusion flow and oxygen consumption rate were measured at 30 second intervals. UTP decreased the perfusion flow and the oxygen consumption rate, dose-dependently. UTP-induced changes were transient and disappeared in about 10 minutes. Suramin (P2-purinergic antagonist, 100 uM) and indomethacin (cyclooxygenase inhibitor, 20 uM) blocked UTP-induced hemodynamic changes significantly. The effects of UTP were also inhibited when Kupffer cells were damaged with treatment of gadolinium chloride (10 mg/kg iv). L-NAME (1 mM), a potent inhibitor of nitric oxide synthase, markedly enhanced and prolonged the contractile response of UTP in the hepatic vessel. These results suggest that UTP acts mainly on suramin-sensitive UTP receptors on the Kupffer cell through prostanoid synthesis. The nitric oxide systems in the endothelium seem to counteract the vasoconstrictile action of UTP in the hepatic circulation.

Erratum to “The association between pentraxin 3 and insulin resistance in obese children at baseline and after physical activity intervention” [Clin. Chim. Acta 413 (2012) 1430–1437] Sang Hui Chu, Ji-Hye Park, Mi Kyung Lee, Yoonsuk Jekal , Ki Yong Ahn, Jae Youn Chung, Dong Hoon Lee, Eun Sung Kim, Masayo Naruse, Jee-Aee Im, In Deok Kong, Choon Hee Chung, Ji Won Lee, Kyong-Mee Chung, Young-Bum Kim⁎, Justin Y. Jeon⁎⁎

Hollow-sphere-shaped nanocapsules containing intentionally inserted magnetic nanoparticles and predefined anticancer drugs provide a powerful magnetic vector under moderate gradient magnetic fields. They enable the nanocapsules to penetrate into the tumors and allow a controlled on-off switchable release of the anticancer drug cargo inside the tunors by remotely applied RF magnetic field. This smart drug delivery system, which can also be made imageable, is compact in geometry because the drug molecules and magnetic nanoparticles can all be self-contained within ∼150 nm capsules. In vitro results indicate that the nanocapsules are effective in reducing tumor cell growth.

It is demonstrated that an incorporation of double-walled carbon nanotubes (DWCNTs) into a TiO2 photo-anode layer results in a significant improvement in the overall energy conversion performance in the dye-sensitized solar cell (DSSC). Comparing to the standard TiO2 anode, the carbon nanotube-containing TiO2 anode with 0.2 wt. % DWCNTs has boosted up the photocurrent density (Jsc) by 43%. The DSSC power conversion efficiency was also improved from ∼3.9% in the case of carbon nanotube-free TiO2 anode to as high as 6.4% with the addition of DWCNTs upon optimized anode annealing. The observed enhancement in the solar cell performance in the presence of the carbon nanotubes is attributed primarily to the noticeable reduction in microcracking and associated robust electrical conduction. Some contribution of the electrical conducting nature of the filler material (DWCNTs) to the improved DSSC properties may be possible; however, it is viewed as a minor effect, considering the small amount of the nanotubes used.

AIM: To investigate serotonergic Ca2+ signaling and the expression of 5-hydroxytryptamine (5-HT) receptors, as well as Ca2+ transporting proteins, in hepatic stellate cells (HSCs). METHODS: The intracellular Ca2+ concentration ([Ca2+]i) of isolated rat HSCs was measured with a fluorescence microscopic imaging system. Quantitative PCR was performed to determine the transcriptional levels of 5-HT receptors and endoplasmic reticulum (ER) proteins involved in Ca2+ storage and release in cultured rat HSCs. RESULTS: Distinct from quiescent cells, activated HSCs exhibited [Ca2+]i transients following treatment with 5-HT, which was abolished by U-73122, a phospholipase C inhibitor. Upregulation of 5-HT2A and 5-HT2B receptors, but not 5-HT3, was prominent during trans-differentiation of HSCs. Pretreatment with ritanserin, a 5-HT2 antagonist, inhibited [Ca2+]i changes upon application of 5-HT. Expression of type 1 inositol-5’-triphosphate receptor and type 2 sarcoplasmic/endoplasmic reticulum Ca2+ ATPase were also increased during activation of HSCs and serve as the major isotypes for ER Ca2+ storage and release in activated HSCs. Ca2+ binding chaperone proteins of the ER, including calreticulin, calnexin and calsequestrin, were up-regulated following activation of HSCs. CONCLUSION: The appearance of 5-HT-induced [Ca2+]i response accompanied by upregulation of metabotropic 5-HT2 receptors and Ca2+ transporting/chaperone ER proteins may participate in the activating process of HSCs.

This paper presents a pH-sensitive bifunctional crosslinker that enables facile conjugation of small molecule therapeutics to macromolecular carriers for use in drug delivery systems. This N-ethoxybenzylimidazole (NEBI) bifunctional crosslinker was designed to exploit mildly acidic, subcellular environments to trigger the release of therapeutics upon internalization in cells. We demonstrate that an analog of doxorubicin (a representative example of an anticancer therapeutic) conjugated to human serum albumin (HSA, a representative example of a macromolecular carrier) via this NEBI crosslinker can internalize and localize into acidic lysosomes of ovarian cancer cells. Fluorescence imaging and cell viability studies demonstrate that the HSA-NEBI-doxorubicin conjugate exhibited improved uptake and cytotoxic activity compared to the unconjugated doxorubicin analog. The pH-sensitive NEBI group was also shown to be relatively stable to biologically-relevant metal Lewis acids and to serum proteins, supporting that these bifunctional crosslinkers may be useful for constructing drug delivery systems that will be stable in biological fluids such as blood.

Purpose This study examined the expression and function of inward rectifier K+ channels in cultured rat hepatic stellate cells (HSC). Materials and Methods The expression of inward rectifier K+ channels was measured using real-time RT-PCR, and electrophysiological properties were determined using the gramicidin-perforated patch-clamp technique. Results The dominant inward rectifier K+ channel subtypes were Kir2.1 and Kir6.1. These dominant K+ channel subtypes decreased significantly during the primary culture throughout activation process. HSC can be classified into two subgroups: one with an inward-rectifying K+ current (type 1) and the other without (type 2). The inward current was blocked by Ba2+ (100 µM) and enhanced by high K+ (140 mM), more prominently in type 1 HSC. There was a correlation between the amplitude of the Ba2+-sensitive current and the membrane potential. In addition, Ba2+ (300 µM) depolarized the membrane potential. After the culture period, the amplitude of the inward current decreased and the membrane potential became depolarized. Conclusion HSC express inward rectifier K+ channels, which physiologically regulate membrane potential and decrease during the activation process. These results will potentially help determine properties of the inward rectifier K+ channels in HSC as well as their roles in the activation process.

Purpose: Serotonin has effects on the bladder contraction or urethral sphincter tone. Different subtypes of 5-hydroxytriptamine (5-HT) receptors appear to mediate the effects of serotonin on voiding. 5-HT1 and 5-HT2, metamorphic receptors, are examined well. However 5-HT3, ionotrophic receptors, are not examined well. Pelvic ganglia provide the majority of the innervation of the lower urinary tract. Major pelvic ganglia (MPG) in rats are autonomic ganglia, containing both sympathetic and parasympathetic neurons related with voiding. We examined the modulatory role of adenylyl cyclase (AC) and protein kinase A (PKA) in 5-HT3 induced intra cellular calcium increase in rat MPG. Materials and Methods: The regulatory effects by AC and PKA were investigated in a single neuron of male rat major pelvic ganglia using patch clamp and fluorescence Ca measurement techniques. Results: Inward currents were induced by 5-HT (10μM) at only parasympathetic neurons of MPG. MDL7222 (10M), selective 5-HT3 receptor antagonists, completely abolished the 5-HT induced inward currents. 5-HT (10μM) induced intracelluar increases of calcium. These increases were blocked by an AC inhibitor SQ22536 (2x10M) and myristoylated PKA inhibitor (10M). Furthermore, foskolin (10M), AC activator, augmented the 5-HT induced intracellular calcium increase. Conclusions: The activation of AC/PKA-dependent pathway could enhance 5-HT3 induced intacellular calcium increase in parasympathetic neurons of rat MPG and these is helpful for the better understanding the mechanisms of the bladder contraction or urethral sphincter tone. (Korean J Urol 2006;47:541-547)

Hepatic stellate cells (HSCs) are known to play a role in the pathogenesis of the increased intrahepatic vascular resistance found in chronic liver diseases. The aim of this study was to evaluate the K+ and Ca2+ currents in cultured HSCs from rat liver, through the patch-clamp technique. Most cells were positive for desmin immunostain after isolation and in alpha-smooth muscle actin immunostain after 10 - 14 days of culturing. Outward and inward rectifying K+ currents were confirmed. Two different types of K+ currents were distinguished: one with the inward rectifying current and the other without. The outward K+ currents consisted of at least four components: tetraethylammonium (TEA)-sensitive current, 4-aminopyridine (4-AP)-sensitive current, pimozide-sensitive current and three blocker-resistant current. The peaks of the outward K+ currents evoked by a depolarizing pulse were decreased to 32.0 +/- 3.0, 62.8 +/- 3.7 and 32.8 +/- 3.5% by 5 mM TEA, 2 mM 4-AP and 15 micro M pimozide, respectively. Moreover, the combined application of three blockers caused 86.6 +/- 4.8% suppression. The inward currents evoked hyperpolarizing pulses were inwardly rectifying and almost blocked by Ba2+. Elevation of external K+ increased the inward current amplitude and positively shifted its reversal potential. Voltage- dependent Ca2+ currents which were completely abolished by Cd2+ and nimodipine were detected in 14 day cultured HSCs. In this study, the cultured HSCs were found to express outward K+ currents composed of multiple pharmacological components, Ba2+-sensitive inward rectifying K+ current and L-type Ca2+ current.

Background: : : :Extracellular ATP, released from platelets and nerve endings, plays significant roles in the regula- tion of circulation. The effects of ATP depend on the location of the vessels and the species of experimental animals. Until now, studies were limited to arteries, so we compared the effects of ATP in rat vena cava with those in the aorta and attempted to identify the characteristics of their receptors. Methods:Vascular rings were isolated from the rat inferior vena cava and descending thoracic aorta. Endothelial cells were preserved or removed by gentle rubbing. The isometric contractions were recorded on polygraph using a force transducer. Results:In the vena cava ring precontracted by 100 nM norepinephrine (NE, ATP elicited relaxations in a dose-dependent manner. These effects were abolished by removal of the endothelium or pretreatment with a nitric oxide synthase inhibitor. Relaxations to ATP in the vena cava (EC50:9.9 μ M were less potent than those in the aorta (1.7 μ M. The relative order of potencies was ADP> ATP >AMP>adenosine, but the maximal relaxation to ADP was smaller than to ATP. ATP-induced vasorelaxation was blocked by suramin, a nonselective antagonist for P2 purinoceptor and reactive blue-2, a P2Y blocker. At basal tension, ATP contracted the vena cava dose-dependently and these effects were potentiated by endothelium-removal. Contractions in the vena cava were also less potent than in the aorta, and the order of potencies was α , β -MeATP>UTP> ATP>ADP>AMP=adenosine. ATP-induced vasoconstriction was blocked by suramin and α , β-MeATP, a desensitizing antagonist of P2X purinoceptor, and potentiated by pretreatment with UTP. Conclusion:These results suggest that ADP and ATP acts on P2Y1- and P2Y2-purinoceptor in the endothelium, respectively and induces vasorelaxation of the vena cava, which is mediated by nitric oxide. Since ATP and UTP induced vasoconstriction in endothelium-denuded condition, it may be mediated by the activation of the P2X and P2Y4,6 purinoceptor on smooth muscles, respectively. (Korean Circulation J 2000;30(9 :1156-1164

The most common cardiovascular side effects of antidepressants are cardiac arrhythmias and orthostatic hypotension. Little is known, however, about the mechanisms by which these adverse reactions may occur, especially with regard to newer drugs such as fluoxetine. We hypothesized that these side effects may have an electrophysiological basis at the level of the cardiac myocyte. Thus, we investigated the effects of fluoxetine and other antidepressants on action potentials and ionic currents of rat ventricular myocytes using the amphotericin B perforated patch clamp technique. Fluoxetine (10 microM) prolonged the action potential duration (APD50) to 146.7 +/- 12.9% of control value without altering resting membrane potential. Fluoxetine and sertraline potently inhibited the L-type Ca2+ current (IC50 = 2.82 and 2.31 microM, respectively), but did not significantly modify the steady-state inactivation. Amitriptyline and imipramine had similar, but slightly weaker, effects (IC50 = 3.75 and 4.05 microM, respectively). Fluoxetine attenuated the peak transient outward K+ current and also altered current kinetics, as shown by accelerated decay. Fluoxetine did not change the voltage-dependence of the steady-state inactivation. Sertraline, amitriptyline and imipramine inhibited the transient outward K+ current with potencies very similar to fluoxetine. In contrast to the other antidepressants tested, trazodone weakly inhibited the Ca2+ and K+ currents and moclobemide had no detectable effect. Our comparative pharmacology data suggest that selective serotonin reuptake inhibitors, such as fluoxetine, are as potent as tricyclic antidepressants in inhibiting L-type Ca2+ and transient outward K+ currents. These inhibitory effects may contribute to cardiovascular complications such as arrhythmias and orthostatic hypotension.

Effects of a platelet-released, naturally occurring nucleotide, adenosine 5'-tetraphosphate (ATPP) on vascular tone were analyzed in the isolated rat aorta. Under resting tension ATPP (1 approximately 100 microM) elicited concentration-dependent contractions in endothelium-intact aortic rings in contrast to the concentration-dependent relaxation with ATP. In endothelium-denuded aortic rings, ATPP induced contraction, as ATP did, but with a greater potency. alpha, beta-methylene ATP (APCPP 50 microM), a P2x-purinoceptor antagonist, significantly inhibited ATPP- as well as ATP-induced contractions in the endothelium-denuded preparations suggesting that ATPP acts via P2x-purinoceptors. ATPP (10 approximately 100 microM) relaxed precontracted aortic rings with an intact endothelium in a concentration-dependent manner. This effect of ATPP was 3.7 fold less potent than that of ATP. However, after P2x-purinoceptor blockade, the effect became identical between the two nucleotides. Reactive blue 2, a selective antagonist of P2x-purinoceptors, significantly attenuated the ATPP-induced relaxation with no change in the ATP-induced relaxation. These results indicated that the rat aortic endothelium contains heterogeneous populations of P2-purinoceptors (possibly P2y and nucleotide receptors). Since ATPP shows dual effects depending upon the vascular tension, it may play a significant role in the physiological regulation of vascular tone.