The present research was designed to investigate whether endothelin-1 (ET-1) secretion can be induced by oxyhemoglobin and whether nuclear factor kappa B (NF-kappa B) is involved in the regulation of ET-1 transcription in cerebrovascular muscle cells. Cerebrovascular muscle cells isolated from a rabbit basilar artery were stimulated by oxyhemoglobin (OxyHb) and ET-1 production was increased significantly in the supernatant. Inhibition of NF-kappa B with pyrrolidine dithiocarbamate and small interfering RNA decreased the expression of ET-1. Nuclear translocation of NF-kappa B and the degradation of IkB-alpha was observed with the stimulation of OxyHb. The supernatant obtained from cerebrovascular muscle cells stimulated by OxyHb produced contractions in arterial rings and was blocked by the ET-1 receptor antagonist (BQ-123). The time course of the OxyHb-induced contractions of the basilar artery rings correlated with the time course of the OxyHb-induced ET-1 secretion. The contraction of the basilar artery rings induced by OxyHb was attenuated when the artery rings were preincubated with pyrrolidine dithiocarbamate and SN50 (20 and 10 mu M, respectively). These results indicate that cerebrovascular muscle cells may be an important source of ET-1 production after subarachnoid hemorrhage. NF-kappa B was involved in the expression of ET-1 and the inhibition of the NF-kappa B pathway may be beneficial for the treatment of cerebral vasospasm. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.

背景:黄芪具有显著的利尿作用,作用时间长,并且对肾炎有一定的对抗作用。目的:观察黄芪对豚鼠离体膀胱逼尿肌条收缩活动的影响,并初步探讨其作用机制。设计、时间及地点:随机对比观察实验,于2005-08/2006-02在兰州大学基础医学院生理学与心理学研究所完成。材料:实验动物选用普通级医学实验动物三色毛豚鼠,雌雄不拘,体质量350～450g。方法:猛击豚鼠头部致昏,迅速取出豚鼠膀胱,切取2条6mm×2mm纵行肌条置于灌流肌槽中,一端与肌肉张力换能器连接,记录肌条的等长收缩活动。待肌条自发活动平稳后加入药物。黄芪采用累计加药法,累计浓度依次为1%,3%,10%,30%,100%,200%,加药间隔2min;加入阻断剂2min后再累计加入不同浓度的黄芪,加入的阻断剂分别为维拉帕米、酚妥拉明、阿托品、六烃季铵。主要观察指标:黄芪及拮抗剂加黄芪对豚鼠离体膀胱逼尿肌条收缩活动的影响。结果:黄芪剂量依赖性增加膀胱逼尿肌条的张力、收缩波平均振幅（r=0.928,0.962,P＜0.01）,较高浓度时增加收缩频率（P＜0.01）。维拉帕米使黄芪增加逼尿肌条收缩张力的作用明显减弱,但不影响黄芪增加逼尿肌条收缩波平均振幅和收缩频率的作用。酚妥拉明使黄芪增加逼尿肌条收缩张力和收缩频率的作用明显减弱,但不影响黄芪增加逼尿肌条收缩波平均振幅的作用。阿托品使黄芪增加逼尿肌条收缩张力、收缩波平均振幅和收缩频率的作用明显减弱。六烃季铵基本不影响黄芪对于膀胱逼尿肌条的作用。结论:黄芪呈剂量依赖性增加膀胱逼尿肌条张力的作用可能是通过激动L-电压依赖性钙通道、α受体和M受体实现的;剂量依赖性增加收缩波平均振幅的作用可能是通过激动M受体实现的;较高浓度时增加收缩频率的作用可能是部分通过激动M受体和α受体实现的。

AIM:To observe the effect of Fructus Psoraleae on motility of isolated gallbladder muscle strips of guinea pigs and its mechanism. METHODS:Guinea pigs were hit to lose consciousness and the whole gallbladder was removed quickly. Two or three smooth muscle strips (8 mm x 3 mm) were cut along a longitudinal direction. The mucosa was gently removed. Every longitudinal muscle strip was suspended in a tissue chamber which was continuously perfused with 5 mL Krebs solution (37 degrees of C), pH 7.4, and aerated with 950 mL/L O2 and 50 mL/L CO2. The isometric response was recorded with an ink-writing recorder. After 2 h equilibration under 1 g-load, 50 microL Fructus Psoraleae (10, 20, 70, 200, 700, 1000 g/L) was added cumulatively into the tissue chamber in turn every 2 min to observe their effects on gallbladder muscle strips (cumulating final concentration of Fructus Psoraleae was 0.1, 0.3, 1.0, 3.0, 10.0, 20.0 g/L). The antagonists, including 4-DAMP, benzhydramine, hexamethonium, phentolamine, verapamil and idomethine were given 2 min before Fructus Psoraleae respectively to investigate the mechanisms involved. RESULTS:Fructus Psoraleae dose-dependently increased the resting tension (r = 0.992, P < 0.001), decreased the mean contractile amplitude (r = 0.970, P < 0.001) and meanwhile increased the contractile frequency of the gallbladder muscle strip in vitro (r = 0.965, P < 0.001). The exciting action of Fructus Psoraleae on the resting tension could be partially blocked by 4-DAMP (the resting tension decreased from 1.37 +/- 0.41 to 0.70 +/- 0.35, P < 0.001), benzhydramine (from 1.37 +/- 0.41 to 0.45 +/- 0.38, P < 0.001), hexamethonium (from 1.37 +/- 0.41 to 0.94 +/- 0.23, P < 0.05), phentolamine ( from 1.37 +/- 0.41 to 0.89 +/- 0.22, P < 0.01) and verapamil (from 1.37 +/- 0.41 to 0.94 +/- 0.26, P < 0.05). But the above antagonists had no significant effect on the action of Fructus Psoraleae-induced mean contractile amplitude (P > 0.05). Moreover, the increase of the contractile frequency due to Fructus Psoraleae was inhibited by 4-DAMP (decreased from 8.3 +/- 1.2 to 6.8 +/- 0.5, P < 0.01) and hexamethonium (from 8.3 +/- 1.2 to 7.0 +/- 0.9, P < 0.05). Idomethine had no significant effect on the Fructus Psoraleae-induced responses (P > 0.05). CONCLUSION:Fructus Psoraleae enhances the motility of isolated gallbladder muscle strips from guinea pigs, in a dose-dependent manner. The effect of Fructus Psoraleae is partly related to M3, N receptor, alpha receptor, H1 receptor, Ca2+ channel, but not related to prostaglandin.

AIM To investigate whether the relaxation characteristics of phytoestrogens resveratrol and phloretin on contractile response of aortic strips are similar to that of estrogen and the mechanisms underground. METHODS Aortic strips from rabbits were suspended in organ baths containing Krebs solution, and then isometric tension was measured. RESULTS Resveratrol and phloretin inhibited the contractile responses to norepinephrine (NE), KCl and CaCl2, shifted their concentration-response curves rightward with pD2′ values of 2.89, 3.34, 3.37 for resveratrol and 3.23, 3.52, 3.77 for phloretin respectively. Also both of them concentration-dependently relaxed KCl-precontracted aortic strip. The relaxing response of resveratrol but not of phloretin in aortic strip was significantly reduced by removal of endothelium or incubation with Nω-L-nitro-arginine and methylthioninium chloride, however both their relaxant effects were not affected by indometacin and propranolol. In Ca2+-free Krebs solution containing 0.01 mmol·L-1 EGTA, resveratrol and phloretin inhibited NE-induced contraction which was caused by Ca2+ release from intracellular store, but did not affect the contraction which was induced by Ca2+ influx. CONCLUSION Resveratrol and phloretin can induce vasorelaxations which may relate to inhibition of Ca2+ influx through potential-dependent calcium channels and Ca2+ release from intracellular stores, and the relaxing response of resveratrol is endothelium-dependent in part, but of phloretin is not endothelium-dependent.

AIM:To study the effects of rhubarb (dried root of Rheum officinale Baill.) on contractile activity of isolated gastric muscle strips of guinea pigs and its possible mechanism.METHODS:A total of 48 guinea pigs were killed to remove the whole stomach. Then, the stomach was opened and the mucosal layer was removed. Parallel to the circular fibers, muscle strips were cut from the body. Each isolated gastric muscle strip was suspended in a tissue chamber containing 5 mL Krebs solution, constantly warmed by water jacket at 37 degrees and bubbled continuously with a mixed gas of 950 mL/L O2 and 50 mL/L CO2. After being incubated for 1 h with 1 g tension, rhubarb of varied concentrations (1%, 2%, 7%, 20% and 70%) was added cumulatively into the tissue chamber at intervals of 2 min. Atropine (10(-6) mol/L) or isoptin (5 x 10(-8) mol/L) or hexamethonium (10(-5) mol/L) was given 2 min before the administration of rhubarb. The isometrical response was measured with an ink-writing recorder.RESULTS:Rhubarb dose dependently increased the resting tension of gastric body circular muscle (CM) (r = 0.726, P<0.05). Atropine (r = 0.829, P<0.05), isoptin (r = 0.764, P<0.05) and hexamethonium (r = 0.797, P<0.05) did not affect its action in a dose-related manner. Atropine apparently reduced the increasing action of 1%, 3%, 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Isoptin inhibited the effect of 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Hexamethonium reduced the increasing action of 1%, 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Rhubarb increased the contractile frequency of CM of body. While atropine, isoptin and hexamethonium did not inhibit the contractile frequency of gastric body CM in comparison with rhubarb at the same concentration, rhubarb at the highest concentration (100%) decreased the mean contractile amplitude of gastric body CM. Atropine, isoptin and hexamethonium did not affect the mean contractile amplitude of gastric body CM compared to rhubarb at the same concentration.CONCLUSION:Rhubarb has exciting actions on isolated gastric smooth muscle strips of guinea pig. The exciting action of rhubarb is partly mediated via cholinergic M receptor, cholinergic N receptor and L-type calcium channel.

AIM To investigate the effect of rhubarb on contractile response of isolated gallbladder muscle strips from guinea pigs and its mechanism. METHODS Guinea pigs were killed to remove the whole gallbladder. Two or three smooth muscle strips (8 mm x 3 mm) were cut along the longitudinal direction. The mucosa on each strip was carefully removed. Each longitudinal muscle strip was suspended in a tissue chamber containing 5 mL Krebs solution (37 degrees), bubbled continuously with 950 mL/L O(2) and 50 mL/L CO(2). The resting tension (g), mean contractile amplitude (mm), and contractile frequency (waves/min) were simultaneously recorded on recorders. After 2-h equilibration, rhubarb (10, 20, 70, 200, 700, 1,000 g/L) was added cumulatively to the tissue chamber in turns every 2 min to observe their effects on gallbladder. Antagonists were given 3 min before administration of rhubarb to investigate the possible mechanism. RESULTS Rhubarb increased the resting tension (from 0 to 0.40+/-0.02, P<0.001), and decreased the mean contractile amplitude (from 5.22+/-0.71 to 2.73+/-0.41, P<0.001). It also increased the contractile frequency of the gallbladder muscle strips in guinea pigs (from 4.09+/-0.46 to 6.08+/-0.35, P<0.001). The stimulation of rhubarb on the resting tension decreased from 3.98+/-0.22 to 1.58+/-0.12 by atropine (P<0.001), from 3.98+/-0.22 to 2.09+/-0.19 by verapamil (P<0.001) and from 3.98+/-0.22 to 2.67+/-0.43 by phentolamine (P<0.005). But the effect was not inhibited by hexamethonium (P>0.05). In addition, the action of mean amplitude and frequency was not inhibited by the above antagonists. CONCLUSION Rhubarb can stimulate the motility of isolated gallbladder muscle strips from guinea pigs. The stimulation of rhubarb might be relevant with M receptor, Ca(2+) channel and alpha receptor partly.

OBJECTIVE:To investigate the effects of hops on obesity in ovariectomy rats. MEHTODS: After ablating bilateral ovarian, adult Sprague-Dawley rats were drinken water extracts of hops and its effects on body weight were observed. On the seventh weekend, blood was collected to assay serum free fat acid (FFA), total anti-oxidative capacity (T-AOC), malondialdehyde (MDA), estrogen, testosterone and insulin. RESULTS:Compared with SHAM group, rats in OVX group displayed the higher weight, serum FFA, MDA and levels of insulin, lower serum levels of estrogen and testosterone and T-AOC. After drinken water extracts of hops, compared with OVX group, rats in OVX + hops group had lower weight, serum FFA, MDA, levels of insulin and higher serum T-AOC. CONCLUSION:Hops could promote weight loss in OVX rats. Hops maybe have estrogen activity. It can increase sensibitity of insulin and elevate anti-oxidative capacity.

AIM To study the effect of progesterone on contractile activity of isolated gastric strips in rats. METHODS Wistar rats were sacrificed to remove whole stomach. Then, the stomach was opened and the mucosal layer was removed. Parallel to either the circular or the longitudinal fibers, muscle strips were cut from fundus, body, antrum and pylorus. Each muscle strip was suspended in a tissue chamber containing 5 mL Krebs solution. Then the motility of gastric strips in tissue chambers was simultaneously recorded. The preparations were subjected to 1 g load tension and washed with 5 ml Krebs solution every 20 min. After 1 h equilibration, progesterone or antagonists were added in the tissue chamber separately. The antagonists were added 3 min before using progesterone (50 micromol/L(-1)). RESULTS Progesterone decreased the resting tension of fundus and body longitudinal muscle (LM) (P<0.05). It inhibited the mean contractile amplitude of body and antrum LM and circular muscle (CM), and the motility index of pyloric CM (P<0.05). The inhibition of progesterone on the mean contractile amplitude could be partially blocked by phentolamine in LM of the stomach body (the mean contractile amplitude of body LM decreased from -7.5+/-5.5 to -5.2+/-4.5 P<0.01), and by phentolamine or indomethacin in CM of body (The inhibition of progesterone on the mean contractile amplitude of body CM decreased from -5.6+/-3.0 to -3.6+/-2.7 by phentolamine and from -5.6+/-3.0 to -3.5+/-2.5 by indomethacin, P<0.01). Hexamethonium, propranolol and L-NNA (inhibitor of NO synthetase) didn't affect the action of progesterone (P>0.05). CONCLUSION The study suggested that progesterone can inhibit the contractile activity of isolated gastric strips in rats and the mechanism seems to be a direct one except that the action on gastric body is mediated through prostaglandin and adrenergic alpha receptor partly.

AIM:To investigate the effects of areca on the contractile activity of isolated colonic muscle strips in rats and mechanism involved. METHODS:Each strip (LMPC, longitudinal muscle of proximal colon; CMPC, circular muscle of proximal colon; LMDC, longitudinal muscle of distal colon; CMDC, circular muscle of distal colon.) was suspended in a tissue chamber containing 5 mL Krebs solution (37 degrees C), bubbled continuously with 950 mL.L(-1) O(2) and 50 mL.L(-1) CO(2). The mean contractile amplitude (A), the resting tension (T), and the contractile frequency (F) were simultaneously recorded on recorders. RESULTS:Areca dose dependently increased the mean contractile amplitude, the resting tension of proximal and distal colonic smooth muscle strips in rats (P<0.05). It also partly increased the contractile frequency of colonic smooth muscle strips in rats (P<0.05). The effects were partly inhibited by atropine (the resting tension of LMPC decreased from 0.44 +/- 0.12 to 0.17 +/- 0.03; the resting tension of LMDC decreased from 0.71 +/- 0.14 to 0.03 +/- 0.01; the mean contractile amplitude of LMPC increased from -45.8 +/- 7.2 to -30.5 +/- 2.9; the motility index of CMDC decreased from 86.6 +/- 17.3 to 32.8 +/- 9.3; P<0.05 vs areca), but the effects were not inhibited by hexamethonium (P>0.05). CONCLUSION:Areca stimulated the motility of isolated colonic smooth muscle strips in rats. The stimulation of areca might be relevant with M receptor partly.

The purpose of this study was to assess the direct effect of progesterone on rabbit pulmonary arteries and to examine the mechanism of its action. Rings of pulmonary artery from male rabbits were suspended in organ baths containing Krebs solution, and isometric tension was measured. The response to progesterone was investigated in arterial rings contracted with noradrenaline (NA), KCl, and CaCl2. The effects of endothelium, nitric oxide (NO), prostaglandins, cyclic GMP (cGMP), and the adrenergic beta-receptor on progesterone-induced relaxation were also assessed. Progesterone inhibited the vasocontractivity to NA, KCl, and CaCl2, and relaxed rabbit pulmonary artery. The relaxing response of progesterone in pulmonary artery was significantly reduced by removal of endothelium, inhibitors of nitric oxide synthase and guanylate cyclase, but not by prostaglandin synthase inhibitor and blockage of the adrenergic beta-receptor. In Ca2+-free (0.1 mM EGTA) Krebs solution, progesterone inhibited NA-induced contraction that was intracellular Ca2+-dependent, but didn't affect the contraction of extracellular Ca2+-dependent component. Our results suggest that progesterone induces relaxation of isolated rabbit pulmonary arteries partially via NO and cGMP. Progesterone may also inhibit Ca2+ influx through potential-dependent calcium channels (PDCs) and Ca2+ release from intracellular stores.

AIM:To study the effect of cholecystokinin-octapeptide (CCK-8) and secretin on contractile activity of isolated gastric muscle strips in guinea pigs.METHODS:Each isolated gastric muscle strip was suspended in a tissue chamber containing 5mL Krebs solution constantly warmed by water jacked at 37° and supplied with a mixed gas of 95% O(2) and 5% CO(2). After incubating for 1h under 1g tension, varied concentrations of CCK-8 and secretin were added respectively in the tissue chamber and the contractile response was measured isometrically on ink-writing recorders.RESULTS:CCK-8 could increase (1) all regional circular and longitudinal muscular tension at rest (fundus LM 19.7% ± 2.1%, P < 0.01; fundus CM 16.7% ± 2.2%, P < 0.01; gastric body LM 16.8% ± 2.3%, P < 0.01; body CM 12.7% ± 2.6%, P <0.01; antrum LM 12.3% ± 1.3%, P < 0.01; antrum CM 16.7% ± 4.5%, P < 0.01; pylous CM 12.7% ± 5.0%, P < 0.05);(2)contractile frequencies of body LM, both LM and CM of antrum and pylorus CM (5.1/min ± 0.2/min to 5.6/min ± 0.2/min, 5.9/min ± 0.2/min to 6.6/min ± 0.1/min, 5.4/min ± 0.3/min to 6.3/min ± 0.4/min, 1.3/min ± 0.2/min to 2.3/min ± 0.3/min, respectively, P < 0.05); the mean contractile amplitude of antral circular muscle (58.6% ± 18.4%, P < 0.05) and (3)the motility index of pylorus CM (145.0% ± 23.8%, P < 0.01), but decrease the mean contractile amplitude of gastric body and antral LM (-10.3% ± 3.3%, -10.5% ± 4.6%, respectively, P < 0.05 =. All the CCK-8 effects were not blocked by atropine or indomethacin. Secretin had no effect on gastric smooth muscle activity.CONCLUSION:CCK-8 possessed both excitatory and inhibitory action on contractile activity of different regions of stomach in guinea pigs. Its action was not mediated via cholinergic M receptor and endogenous prostaglandin receptor.

The effect of cimetidine and ranitidine on small intestinal longitudinal strips in rats was studied. The results showed that: (1) cimetidine 4 mmol · L-1 decreased the mean contractile amplitude of ileal strips, but ranitidine 2 mmol · L-1 increased it; (2) cimetidine 1 - 4 mmol · L-1 and ranitidine 5 mmol · L-1 inhibited contractile motility of duodenal, proximal jejunal and distal jejunal strips, while ranitidine 2 mmol · L-1 stimulated contractile motility of these strips. These results suggest that: (1) cimetidine inhibit contractile activity of ileal strips, but ranitidine excite it; (2) the inhibitory action of cimetidine and ranitidine on duodenal, proximal jejunal and distal jejunal strips not be mediated by H2-receptor.