Effect of Fructus Psoraleae on motility of gallbladder isolated smooth muscle strips from guinea pigs

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×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℃), 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, 50μL 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 Psoraleaeinduced 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, a receptor, H1 receptor, Ca2 channel, but not related to prostaglandin.     

Actions of genistein on contractile response of smooth muscle isolated from guinea pig gallbladder

BACKGROUND:Defective contractile motility of the gallbladder is an important factor for gallstone formation.Estrogen might increase the risk of gallstones and cholecystitis,and estradiol inhibits the contractile activity of isolated strips of guinea pig gallbladder.The potential risks associated with hormone replacement therapy(HRT) include symptomatic gallstones.Phytoestrogen have been used to treat menopause syndromes by replacing traditional estrogen.This experiment aimed to determine the effects of the ...     

Effects of rhubarb on isolated gastric muscle strips of guinea pigs

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℃ 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 (5x10-8 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, A:0.05), isoptin (r= 0.764, A;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.     

Effect of cholecystokinin and secretin on contractile activity of isolated gastric muscle strips in guinea pigs

AIM To study the effect of cholecystokininoctapeptide (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 containing5 mL Krebs solution constantly warmed by water jacked at 37℃ and supplied with a mixed gas of 95% O2 and 5% CO2. After incubating for 1 h under 1 g 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.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 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,amplitude of antral circular muscle (58.6%±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.     

莱菔子对豚鼠体外胃窦环行肌条收缩活动的影响

[目的]观察莱菔子水煎剂对豚鼠体外胃窦环行肌条的收缩活动并探讨其作用机制。[方法]将胃窦环行肌条置于灌流肌槽内,采用累积加莱菔子和分别加阻断剂的方法,观察其对肌条收缩活动的影响。[结果]莱菔子增大胃窦环行肌条的收缩波平均振幅及其收缩频率,并呈一定剂量依赖关系,M3胆碱能受体拮抗剂4-DAMP可部分阻断其振幅的增大。[结论]莱菔子水煎剂增大豚鼠胃窦环行肌条收缩波平均振幅的作用可能部分经由兴奋胆碱能M3受体而不是胆碱能M2受体。     

氢溴酸槟榔碱对豚鼠体外胃不同部位肌条作用及其机制

[目的]观察氢溴酸槟榔碱（Ah）对豚鼠体外胃不同部位平滑肌肌条收缩运动的影响，并初步探索其作用机制。[方法]用胃不同部位（6处）平滑肌条置于灌流浴槽，在37℃恒温、通氧和Krebs液灌注条件下，分别记录单独使用Ah和阻断剂孵育后Ah的收缩效应。[结果]①Ah可显著增高各部分体外胃平滑肌条的张力，增大收缩振幅和收缩波曲线下面积，2者均比基础值有显著增高（P〈0．05）。而且其效应强度不同部位有明显差异。纵肌效应：Ah对胃窦纵肌的作用振幅大于胃底、胃体（P〈0．01）；效应曲线下面积大于胃体（P〈0．01）。环肌效应：Ah对胃窦环肌作用振幅大于胃底（P〈0．05）；效应曲线下面积大于胃体和胃底（P〈0．05），对胃体环肌作用的曲线下面积亦大于胃底（P〈0．05）。②阿托品和维拉帕米均能部分阻断Ah的收缩作用，显著降低其振幅（P〈0．01）。[结论]Ah对豚鼠体外胃平滑肌条的收缩活动有明显兴奋作用，推测这种效应部分介导于M-胆碱能受体，L型电压依赖性Ca^2＋通道。     

Evidence for the expression of transient receptor potential proteins in guinea pig airway smooth muscle cells

OBJECTIVE: The present study investigates the expression of transient receptor potential (TRPC) proteins in airway smooth muscle (ASM) cells in order to determine whether these proteins may be candidate molecular counterparts of plasma membrane Ca2+-permeable channels involved in the contraction of ASM. METHODS: Expression of TRPC mRNA was detected using specific primers and RT-PCR. Expression of the TRPC1, TRPC3 and TRPC6 proteins was detected using antibodies in immunoprecipitation and Western blot. RESULTS: Guinea pig ASM cells exhibited thapsigargin- and acetylcholine-initiated Ca2+ inflow but none by 1-oleoyl-2-acetyl-sn-glycerol. mRNA encoding each of the TRPC1 to TRPC6 proteins was detected in ASM cells. mRNA encoding TRPC1, TRPC3, TRPC4 and TRPC6 was detected in ASM cells at a concentration approximately equivalent to that in guinea pig brain. mRNA encoding TRPC2 and TRPC5 was more abundant in ASM cells than in brain. The TRPC1 protein, but not the TRPC3 or TRPC6 proteins, was detected in extracts of ASM cells, while all three proteins were detected in brain. CONCLUSION: The results provide evidence for a low level of expression of the TRPC1 to TRPC6 proteins in ASM cells. These proteins may function as store-operated Ca2+ and/or second messenger-activated non-selective cation channels in ASM cells.     

Inhibitory effects of genistein and resveratrol on guinea pig gallbladder contractility in vitro

AIM： To observe and compare the effects of phytoestrogen genistein, resveratrol and 17β-estradiol on the tonic contraction and the phasic contraction of isolated gallbladder muscle strips and to study the underlying mechanisms. METHODS： Isolated strips of gallbladder muscle from guinea pigs were suspended in organ baths containing Kreb＇s solution, and the contractilities of strips were measured before and after incubation with genistein, resveratrol and 17β-estradiol respectively. RESULTS： Similar to 17β-estradiol, genistein and resveratrol could dose-dependently inhibit the phasic contractile activities, they decreased the mean contractile amplitude and the contractile frequencies of gallbladder muscle strips, and also produced a marked reduction in resting tone. The blocker of estrogen receptor ICI 182780 failed to alter the inhibitory effects induced by genistein and resveratrol, but potassium bisperoxo （1, 10 phenanthroline） oxovanadate bpV （phen）, a potent protein tyrosine phosphatase inhibitor, markedly attenuated the inhibitory effects induced by genistein and resveratrol. In calcium-free Kreb＇s solution containing 0.01 mmol/L egtazic acid （EGTA）, genistein and resveratrol inhibited the first phasic contraction induced by acetylcholine （ACh）, but did not affect the second contraction induced by CaCl2. In addition, genistein, resveratrol and 17β-estradiol also could reduce the contractile responses of ACh and KCl, and shift their cumulative concentration-response curves rightward. CONCLUSION： Phytoestrogen genistein and resveratrol can directly inhibit the contractile activity of isolated gallbladder muscle both at rest and in response to stimulation. The mechanisms responsible for the inhibitory effects probably due mainly to inhibition of tyrosine kinase, Ca^2＋ influx through potential-dependent calcium channels （PDCs） and Ca^2＋ release from sarcoplasmic reticulum （SR）, but were not related to the estrogen receptors.     

肺动脉平滑肌细胞上的钙离子通道研究进展

钙离子(Ca2+)为肺动脉平滑肌细胞(PASMC)内至关重要的第二信史,其细胞内浓度的精细变化直接受到多种Ca2+通道的调控.按照细胞内Ca2+的来源,位于细胞膜上,调控细胞外Ca2+进入细胞的通道称为钙内流通道,位于肌质网上调控内质网/肌质网内钙库的Ca2+释放的通道称为钙释放通道.根据Ca2+通道激活方式的不同,C...     

胆汁对兔胃平滑肌条运动的影响

[目的]观察胆汁对兔体外胃平滑肌的影响,并探讨其作用机制.[方法]取兔胃肌条,安置在各恒温灌流肌槽中,并用BL310生物技能实验系统记录胃各部位平滑肌条的收缩活动.[结果]胆汁显著降低兔胃底和胃体纵行肌条张力,减小胃体收缩波平均振幅,并有剂量依赖关系.[结论]胆汁对胃肌条收缩活动具有明显的抑制作用,这种抑制作用部分经由肾上腺素能α受体及前列腺素介导,并有壁内神经节的参与.     

Behavior of nonselective cation channels and large-conductance Ca2+-activated K+ channels induced by dynamic changes in membrane stretch in cultured smooth muscle cells of human coronary artery

INTRODUCTION: The effects of membrane stretch on ion channels were investigated in cultured smooth muscle cells of human coronary artery. METHODS AND RESULTS: In the cell-attached configuration, membrane stretch with negative pressure induced two types of stretch-activated (SA) ion channels: a nonselective cation channel and a large-conductance Ca2+-activated K+ (BK(Ca)) channel. The single-channel conductances of SA cation and BK(Ca) channels were 26 and 203 pS, respectively. To elucidate the mechanism of activation of these SA channels and to minimize mechanical disruption, a sinusoidal change in pipette pressure was applied to the on-cell membrane patch. During dynamic changes in pipette pressure, increases in SA cation channel activity was found to coincide with increases in BK(Ca) channel activity. In the continued presence of cyclic stretch, the activity of SA cation channels gradually diminished. However, after termination of cyclic stretch, BK(Ca) channel activity was greatly enhanced, but the activity of SA cation channels disappeared. CONCLUSION: This study is the first to demonstrate that the behavior of SA cation and BK(Ca) channels in coronary smooth muscle cells is differentially susceptible to dynamic changes in membrane tension.     

调气中药对豚鼠体外胃平滑肌运动的影响

[目的]观察同归脾、胃经具有调理气机功能的莱菔子、大腹皮、白术、小茴香、莪术,香附、蒲公英等7味中药对豚鼠体外胃纵行肌条的收缩作用,探讨其促胃动力作用规律。[方法]制备豚鼠胃底、胃体平滑肌条,以0.85%氯化钠(NS)和乙酰胆碱(ACh)作对照,观察7味中药对豚鼠体外胃纵行平滑肌的收缩效应。[结果]7味中药对胃底胃体纵行肌条均有不同程度的兴奋作用。与NS组比较,差异有统计学意义(P<0.01)。以ACh标化实验数据,莱菔子的收缩作用最强,与大腹皮比较,差异无统计学意义(P>0.05),与其他5味中药比较,差异有统计学意义(P<0.05),白术、蒲公英、小茴香的作用次之,无论在胃体还是胃底,莪术和香附的收缩作用均稍弱,分别与其他5味药比较差异均有统计学意义(P<0.05)。[结论]7味中药均有较强的促胃动力作用,其中莱菔子、大腹皮作用显著,值得进一步开发研究。从脾胃论治,结合气机升降理论开展促胃肠动力中药筛选是一条有效途径。     

Mechanism of leukotriene-induced contraction of isolated guinea pig tracheal smooth muscle

The mechanical response of guinea pig tracheal smooth muscle to leukotriene (LT) B₄, C₄, D₄ and E₄ was investigated, and the effects of several agents on LT-induced contraction were determined. Agents used in the present study were: verapamil, a Ca-channel blocker; dibutyryl cyclic-AMP (DBcAMP); aminophylline; N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7), a calmodulin antagonist; N-(6-aminohexyl)-1-naphthalene-sulfonamide hydrochloride (W-5), resembling W-7 in structure but without calmodulin antagonism. The results were as follows: 1) LTB₄ had a contractile activity, dependent on the [Ca]o concentration; it was suppressed by a [Mg]o increase to 1.2 mM and over. Little effect was observed from other drugs. 2) Contractile activities of LTC₄, D₄ and E₄ were dose-dependent, depending upon [Ca]o as well as LTB₄. 3) Verapamil (5×10⁻⁶−10⁻³ M), DBcAMP (3×10⁻⁶−3×10⁻³ M) and aminophylline (3×10⁻⁸−3×10⁻³ M) suppressed LTs (C₄, D₄, and E₄, 10⁻⁸ M)-induced contraction dose-dependently. However, W-7 and W-5 did not suppress LT-induced contraction. These results suggest that the LTC₄-, D₄-and E₄-induced responses could be explained by the effect of LTC₄, D₄ and E₄ on increasing Ca influx through the plasma membrane.     

Effects of Dangshen on isolated gastric muscle strips in rats

AIM To study the effects of Dangshen [dried root of Codonopsis Pilosula (Franch) Nannf] on contractile activity of isolated gastric muscle strips in rats and its possible mechanism involved.METHODS Each isolated gastric muscle strip was put in a tissue chamber containing 5ml Krebs solution, constantly warmed by water jacket at 37℃ and supplied with a mixed gas of 95% O2 and 5% CO2. After incubating for 1h with 1g tension, Dangshen of varied concentration was added cumulatively in the tissue chamber at intervals of 2 minutes. The isometrical response was measured on ink-writing recorders.RESULTS Dangshen dose dependence increased the resting tension of longitudinal muscle (LM) of fundus (r=0.96, P＜0.01), the mean contractile amplitude of circular muscle (CM) of the stomach body (r=0.87, P＜0.05) and CM of antrum (r=0.98, P＜0.01), and the motility index CM of pylorus (r=0.87, P＜0.05). Atropine (5×10-8mol/L) or Hexamethonium (10-5mol/L) or Indomethacin (5×10-7mol/L) was given 2 minutes before the administration of Dangshen, it did not abolish its dose related manner. Atropine apparently reduced the increasing action of 10% and 30% Dangshen on the resting tesion of LM of fundus (P＜0.05), 30%, 100% and 200% Dangshen on bodied strips (P＜0.05), 100% and 200% Dangshen on antral strips (P＜0.05). Hexamethonium reduced the increasing action of 10% and 30% Dangshen on the resting tesion of LM of fundus (P＜0.05 and P＜0.05), 30%, 100% and 200% Dangshen on bodied strips (P＜0.05), and 100% and 200% Dangshen on pyloric strips (P＜0.05). Indomethacin inhibited the effect of 10% Dangshen on the resting tesion of LM of fundus (P＜0.05), but did not affect the exciting action of Dangshen on strips of body, antrum and pylorus.CONCLUSION The results showed that Dangshen possessed exciting action on the isolated gastric smooth muscle strips of the rat. The exciting action of Dangshen was partially mediated via cholinergic M and N receptors.     

胆道梗阻诱发急性胆囊炎对豚鼠胆囊平滑肌收缩的影响

目的探讨胆道梗阻早期胆囊平滑肌的收缩障碍,并初步探究其相关机制。方法胆总管结扎方法构建豚鼠急性非结石性胆囊炎(AAC)模型,HE染色后光镜下观察各组胆囊病理改变。采用灌流法加药,利用张力换能器记录豚鼠离体胆囊肌条张力的变化,观察8肽胆囊收缩素(CCK-8)、乙酰胆碱(Ach)及氯化钾(KCl)对正常豚鼠离体胆囊肌条(A组)、假手术组(B组)、胆总管结扎1天(C组)、胆总管结扎2天(D组)豚鼠离体胆囊肌条的影响。结果A、B组未见明显炎性改变;C组炎症改变较轻;D组炎性改变明显。加入CCK-8、Ach和KCl后,A组、B组、C组及D组收缩振幅均增加,呈浓度依赖性;C、D两组振幅效应值同A组和B组相比变小,起作用时间慢(P0.05)。结论利用胆总管结扎方法可成功构建AAC模型。离体胆囊肌条肌张力降低在AAC的发生发展中有重要作用。模型组肌条收缩力降低,可能与CCK受体、胆碱能受体相关。     

哮喘豚鼠气管平滑肌钾离子通道特性的改变

目的为探讨哮喘时电压依赖性钾离子通道（ⅠＫ）特性的改变。方法在支气管平滑肌细胞膜上，用膜片钳技术进行了研究。结果哮喘平滑肌细胞有如下改变：（１）静息跨膜电位差值降低。（２）通道电导值与正常组相比下降了约５１％。（３）开放时间常数的快、慢成分明显缩短，分别下降到正常对照组的２５％和７％。关闭时间常数明显延长。（４）开放概率有电压依赖性，但在相同的钳制电压范围内明显降低。结论哮喘气道高反应性时钾离子通道动力学活性明显衰减，提示将导致细胞兴奋阈降低。     

Relaxant effect of omeprazole and lansoprazole in guinea pig gallbladder muscle strips in vitro

Background. The aim of this study was to investigate the role of omeprazole and lansoprazole, H⁺-K⁺ ATPase inhibitors, in gallbladder smooth muscle contractility in vitro. Methods. Gallbladder muscle strips obtained from guinea pigs were mounted in an organ bath. The responses of both precontracted strips and strips under basal tension to omeprazole and lansoprazole were determined. Results. Spontaneous contractile activity was blocked following omeprazole and lansoprazole administration. The agents also caused concentration-dependent relaxation in carbachol- and KCl-precontracted gallbladder muscle strips. Pretreatment with atropine (1µM), N^W-nitro l-arginine methyl ester (l-NAME; 30µM), indomethacin (10µM), ammonium chloride (7.5mM), sodium acetate (7.5mM), tetraethylammonium chloride (0.5mM), glibenclamide (1µM), 4-aminopyridine (0.1mM), or clotrimazole did not inhibit this relaxation. Gallbladder strips were placed in high-concentrtion potassium (80mM), calcium-free solution. The contraction produced with the addition of Ca²⁺ (2.5mM) was completely relaxed by omeprazole, lansoprazole, and nifedipine separately. Conclusions. These results demonstrate that omeprazole and lansoprazole have potent inhibitory effects on spontaneous contractions and cause dose-dependent relaxation in precontracted gallbladder smooth muscle strips of guinea pig in vitro. This effect could be due to blockade of the calcium channels.