腺苷及腺苷三磷酸对大鼠离体结肠平滑肌的作用

目的 比较腺苷和腺苷三磷酸对大鼠离体近端结肠纵行平滑肌活动的调节作用.方法 四导生理记录仪记录大鼠近端结肠纵行肌的等长舒张和收缩反应.结果 对于静息状态下的大鼠离体近端结肠纵行肌标本,腺苷无明显影响(P＞0.05).但是,腺苷三磷酸使静息状态下的大鼠离体近端结肠纵行肌产生微弱的舒张反应后续浓度依赖性收缩反应;腺苷三磷酸的上述作用不受神经阻断剂河豚毒素的影响.大鼠离体近端结肠纵行肌标本在五羟色胺或乙酰胆碱预收缩条件下,腺苷和腺苷三磷酸均可产生浓度依赖性舒张反应,但是腺苷引起的舒张反应明显弱于腺苷三磷酸(P＜0.01).结论 在大鼠离体近端结肠纵行肌,腺苷三磷酸可产生舒张反应和收缩反应,而腺苷仅产生舒张反应.     

催产素对大鼠离体胃平滑肌收缩活动的影响

观察催产素（ｏｘｙｔｏｃｉｎ）对大鼠胃不同部位肌条收缩活动的影响． 结果表明：１０ Ｕ·Ｌ－ １催产素可降低胃底纵行肌张力,升高胃体纵行肌,环行肌和胃窦纵行肌条的张力（升高百分率分别为８±８,３２±２０, ６±８）,增大胃体和胃窦各肌条的收缩波平均振幅及幽门环行肌的运动指数（增大百分率分别为２７±４１, ６２±３８, １２±１５, ３９±１９, ５３±２９）,增快幽门环行肌的收缩频率〔从（１．２±０．３）ｍ ｉｎ－ １ 增至（１．９±０．３） ｍ ｉｎ－ １〕;而１００ Ｕ·Ｌ－ １催产素升高胃体纵行肌和环行肌及胃窦纵行肌张力的同时降低其收缩波平均振幅,增快各肌条的收缩频率． 阿托品和六甲溴铵均不阻断催产素的上述作用． 结果表明催产素可能直接作用于平滑肌细胞,对大鼠离体胃平滑肌收缩活动起兴奋作用．     

牛磺酸对前列腺素E2兴奋大鼠胃底平滑肌作用的影响

目的：观察了牛磺酸对大鼠胃底平滑肌收缩性的影响。方法：采用离体平滑肌实验技术观察胃底条收缩作用。结果：牛磺酸使前列腺素Ｅ２（ＰＧＥ２）累加量效曲线明显降低。结论：牛磺酸能对抗;ＰＧＥ２兴奋大鼠胃底平滑肌作用。     

山楂水提物对大鼠离体胃、肠平滑肌条收缩性的影响研究

目的:研究山楂水提物对大鼠离体胃、肠平滑肌条收缩性的影响。方法:以大鼠离体胃、肠平滑肌条为研究对象,观察在正常克氏液条件下加入山楂水提物后大鼠胃、肠平滑肌条的收缩状况及在乙酰胆碱、阿托品作用下加入山楂水提物后大鼠肠平滑肌条的收缩状况。结果:山楂水提物在5～20mg·mL-1浓度范围内可显著增强大鼠胃、肠平滑肌条的运动,且具有显著剂量依赖性。山楂水提物(20mg·mL-1)可加强乙酰胆碱引起的肠平滑肌的强烈收缩,对抗阿托品引起的肠平滑肌的舒张作用。结论:山楂水提物对大鼠胃、肠平滑肌条的收缩具有显著的刺激作用。     

大黄酸对大鼠离体子宫平滑肌运动的影响

目的观察大黄酸对人工动情期大鼠离体子宫平滑肌条的作用及探讨其作用机制。方法将子宫平滑肌条悬挂于离体平滑肌灌流肌槽装置内,采用累积加药的方法以观察大黄酸对肌条自发运动的影响。结果大黄酸能够抑制大鼠离体子宫平滑肌的收缩活动并具有剂量依赖性关系;酚妥拉明、苯海拉明不能阻断大黄酸对大鼠离体子宫平滑肌的作用;而异搏定、吲哚美辛可完全阻断大黄酸的作用。结论大黄酸对大鼠离体子宫平滑肌条运动的抑制作用,可能是通过作用于平滑肌细胞膜的L-型钙通道及细胞内前列腺素的合成与释放而实现的。     

胃体多发性平滑肌瘤一例

[病例] 男,31岁。因间断上腹部隐痛不适4年,头晕、便血5天入院。患者于4年前出现上腹部隐痛不适,伴反酸、嗳气。疼痛无明显规律性,自服“胃仙U”及对症治疗好转。曾在当地医院行钡餐造影检查,未见异常。因进食后上述症状加重,遂来诊,以急性上消化道出血入院。上消化道造影示胃底后壁向腔内突出的约6cm×8cm分叶状团块阴影。在全麻下行贲门侧胃大部切除,术中见贲门周围有一“亚铃状”肿瘤,食管下段有一3.5cm×2.0cm外生性肿块,贲门口狭窄,胃底右后方有一8.0cm×1.0cm肿块位于腔内。诊断:贲门周围肿瘤。因肿瘤位置高,遂行胸腹联合切口,切除肿瘤。病理诊断:胃体后壁小弯侧粘膜及浆膜下多发性平滑肌瘤。     

阿司匹林对在体及离体气管平滑肌的影响

目的 研究阿司匹林对在体及离体气管平滑肌的影响.方法 本次研究对象为2013年~2016年之间接受治疗的80例患者,随机分成观察组(n=25)、实验组(n=25)和对照组(n=30),采用不同剂量的阿司匹林进行治疗,即对照组使用剂量为100mg,观察组使用剂量为200mg,试验组使用剂量为300mg,比较不同剂量的阿司匹林对在体及离体气管平滑肌的影响.结果 对照组与观察组和实验组哮喘持续时间比较呈逐渐缩短趋势,差异有统计学意义P<0.05;对照组与观察组和实验组哮喘恢复时间比较呈逐渐延长趋势,差异有统计学意义P<0.05.对照组与观察组和实验组的张力值比较呈逐渐增长趋势,差异有统计学意义P<0.05;对照组与观察组和实验组的抑制率比较呈逐渐下降趋势,差异有统计学意义P<0.05.阿司匹林的剂量增加,对抗气管平滑肌收缩的作用随之减弱.结论 较为适量的阿司匹林对气管平滑肌的扩张具有较好的作用功效.     

小儿健脾膏整方及其单味药对大鼠离体胃、回肠平滑肌作用的比较研究

目的 观察比较小儿健脾膏整方及其单味药对大鼠离体胃、回肠平滑肌的作用,辨识该方中具有促胃肠动力的味药,为探讨其药效物质奠定基础。方法 用生物信号采集系统记录小儿健脾膏整方及其单味药对正常大鼠胃、回肠平滑肌收缩张力的变化,并比较其作用大小。结果 整方及其单味药对胃肌收缩的促进作用：整方 > 丁香 > 山楂 > 肉桂,白胡椒作用不显著;对回肠平滑肌的促进作用：丁香 > 整方 > 山楂,肉桂、白胡椒作用不显著;吴茱萸对胃、回肠收缩呈双向调节,小剂量促进,大剂量抑制。结论 小儿健脾膏整方对离体胃、回肠平滑肌收缩有促进作用;单味药中有明显促进作用的是丁香和山楂,吴茱萸呈双向调节作用;丁香和山楂是该方中促胃肠动力作用的主要味药。     

五味子提取物对离体兔肠平滑肌运动影响

目的 研究五味子提取物对离体兔肠平滑肌的舒张作用及机制。方法 采用离体兔肠平滑肌试验,应用BL-420E生物机能实验系统,比较五味子提取物对离体兔肠平滑肌及乙酰胆碱和妥拉唑啉作用下其平滑肌活动的影响,记录肠肌的收缩频率和振幅。结果五味子提取物对离体兔肠平滑肌自发性收缩频率和振幅的抑制作用具有浓度依赖性。40 mg/ml的五味子提取物对由乙酰胆碱引起的离体兔肠平滑肌的兴奋性收缩有明显的抑制作用;当运用妥拉唑啉阻断肾上腺素能α受体后,五味子提取物仍然可以对离体肠平滑肌收缩的振幅具有抑制作用。结论 五味子提取物可能与乙酰胆碱产生竞争性抑制,阻断M受体,舒张小肠平滑肌;也可能与妥拉唑啉相互竞争,兴奋α受体,从而舒张小肠平滑肌。     

The different mechanisms of action of nicorandil and adenosine triphosphate on potassium channels of circular smooth muscle of the guinea-pig small intestine

Summary Nicorandil (10 mol/l–0.3 mmol/l) and ATP (1 mol/l–0.1 mmol/l) hyperpolarized the membrane of circular smooth muscle of the guinea-pig small intestine and increased conductance of the membrane probably to K ions as estimated by the effect on the current-voltage relationship. In the presence of a maximally hyperpolarizing concentration of nicorandil (0.1 mmol/l), ATP produced a further hyperpolarization of 5 mV. The ATP-induced but not the nicorandil-induced hyperpolarization required the presence of Ca in the medium, and the ATP-induced hyperpolarization was blocked by apamin treatment (1 nmol/l) or by MnCl₂ (1.3 mmol/l). On the other hand, both hyperpolarization responses were blocked by the local anaesthetics procaine (0.1–1 mmol/l), lidocaine (0.1–1 mmol/l) or cocaine (0.3–1 mmol/l), with different potencies. Field stimulation of smooth muscle of the small intestine produced inhibitory junction potentials (i.j.p.s) and these were inhibited by apamin (10 nmol/l–100 nmol/l). In the presence of ATP, the amplitude of the i.j.p.s was markedly reduced, but in the presence of nicorandil the amplitude was only slightly reduced, consistent with the same increase in ionic conductance and hyperpolarization of the membrane. These results indicate that ATP and nicorandil hyperpolarize the membrane by activating different K-channels, i.e. Ca dependent and Ca insensitive K channels, respectively. As assessed from the effects of local anaesthetics and the membrane properties, the circular muscle may also possess other K channels different from the ATP and nicorandil sensitive K channels.     

Effects of adenosine and related compounds on adenylate cyclase and cyclic AMP levels in smooth muscle.

The hypotheses were tested that the relaxant effect of adenosine and related compounds in the longitudinal muscle of the rabbit small intestine involves interaction with adenylate cyclase and/or the elevation of tissue cAMP levels. Adenylate cyclase was prepared by gentle homogenization of an isolated smooth muscle cell fraction obtained after collagenase digestion of longitudinal muscle strips. A number of analogs and derivatives of adenosine possessing a primary or secondary 6-amino group were found to inhibit the enzyme similarly to adenosine; however, there was no correlation between compounds known to relax the intact tissue and the existence, or the degree of, cyclase inhibition. Isolated muscle strips were exposed to adrenaline, isoprenaline, adenosine or ATP, at doses causing 30-60% relaxation, for 60 sec prior to sampling and analysis of cAMP content. While small increments in cAMP levels were found after administering adrenaline or isoprenaline, no change was found with adenosine in the absence or presence of theophylline of 1-methyl-3-isobutylxanthine. Neither adenylate cyclase inhibition nor changes in cAMP levels appear to be part of the mechanism of the smooth muscle relaxant action of adenosine or ATP.     

Analysis of the contractile responses of the ileal segment of the isolated blood-perfused small intestine of rats to adenosine triphosphate and related compounds.

For close-arterial injection the isolated small intestine of the rat was perfused by a cross-circulation technique at a fixed flow rate through the superior mesenteric artery with arterial blood from a donor. Single intra-arterial injections of purine derivatives elicited a monophasic fast contraction of the ileum. In order to elucidate the mechanism of the fast contraction, adenosine triphosphate (ATP) was chosen for further investigations. The ileal response to ATP was abolished by tetrodotoxin, hexamethonium or morphine, but was resistant to blockade by atropine, methysergide or mepyramine. These results definitely indicate that ATP causes the fast contraction of the ileum by a stimulation of neuronal elements in the myenteric plexus involving cholinergic interneurons.     

Muscarinic receptors in isolated smooth muscle cells from gastric antrum

Smooth muscle cells from the gastric antrum of the rabbit were isolated using collagenase and pronase. We examined the characteristics of muscarinic receptors that control contraction of the muscle cell: kinetics, stoichiometry and specificity of both contractile response to muscarinic agents and binding of labeled N-methyl-scopolamine. Cells contracted in the presence of muscarinic agents after a short time (30 sec) while binding of (3H)-NMS reached a plateau after 10 min exposure. Specific binding was saturable and Scatchard analysis revealed a single class of high-affinity binding sites (Kd: 0.5 nM). Oxotremorine was the most potent agonist with an ED50 of 0.6 pM; acetylcholine and carbachol were 10 times less potent. Muscarinic antagonists competed with (3H)-NMS for binding with IC50 values in the same range (nanomolar or less) than those obtained for inhibition of acetylcholine-induced contractions. Pirenzepine antagonized contractile effect of muscarinic agonists with EC50 in a micromolar range. Intracellular levels of cyclic AMP were lowered by muscarinic agonists. Monoclonal anti-muscarinic receptor antibodies M-35 displayed agonist-like activities triggering contraction and lowering cyclic AMP levels of the cells. However, although the antagonist inhibits M-35-induced contractions and cAMP decrease, M-35 had no effect on binding of the antagonist to the muscarinic receptor. These data revealed the presence of an M2-muscarinic receptor subtype involved in the contractile response of the isolated smooth muscle cell.     

Effects of 3,3'-di-O-methylquercetin on guinea-pig isolated smooth muscle

The effects of the flavone 3,3'-di-O-methylquercetin (DOMQ) have been examined and compared with those of quercetin, on guinea-pig isolated ileum, trachea, and main pulmonary artery (MPA). Except for transient contractions induced by low concentrations (10(-8)-3 x 10(-6) M), DOMQ and quercetin (up to 3 x 10(-4) M) caused reduction of the tone and the phasic contractions of the ileum. A23187 reversed the inhibitory effects of quercetin but not those of DOMQ. DOMQ and quercetin caused concentration-dependent relaxation of the trachea and the adrenaline-contracted MPA. DOMQ shifted to the right the concentration-effect curves induced by acetylcholine on the ileum and the trachea, and by adrenaline on MPA and those induced by CaCl2 on ileum, trachea and MPA. DOMQ also inhibited the contractions induced, in Ca2+-free EGTA-containing buffer, by histamine on ileum and by adrenaline on MPA. These observations suggest that DOMQ inhibits Ca2+ influx, Ca2+ release from intracellular stores and, more likely, Ca2+ binding to intracellular receptor proteins.     

Effects of adenosine 3′-phosphate 5′-phosphosulfate on P2 receptors in platelets and smooth muscle preparations

Adenosine 3′-phosphate 5′-phosphosulfate (A3P5PS) has been proposed to be a selective antagonist at P2Y₁1 receptors and this receptor subtype has been suggested to be present on human platelets and to be responsible for ADP-induced aggregation. The effects of A3P5PS, therefore, were tested on the responses of human platelets to ADP and also on the relaxation of the rat duodenum, which is also thought to be mediated by means of the P2Y₁ receptor, as well as on the contraction of the vas deferens and urinary bladder, which is thought to be mediated by means of P2X₁ receptors, because the effects of A3P5PS on P2X₁ receptors have not been reported. A3P5PS selectively antagonised in an apparently competitive manner ADP-induced platelet aggregation, as well as the ability of ADP to cause shape change and increases in [Ca²⁺]i in platelets, but had no effect on the inhibition of stimulated adenylate cyclase by ADP, confirming suggestions that this response is mediated by means of a different receptor subtype. A3P5PS did not act as an antagonist in any of the smooth muscle preparations tested, but instead acted as an agonist in the rat duodenum, showing that there are limitations to its use in isolated tissue studies. In addition, A3P5PS was rapidly degraded by enzymes present on the surface of the rat vas deferens, and although its breakdown was slower than that of ATP itself, it may also be a complicating factor in the use of this and similar compounds. Drug Dev. Res. 45:67–73, 1998. © 1998 Wiley-Liss, Inc.     

The effects of electrical stimulation, adenosine and adenosine -5′ triphosphate (ATP) on mouse rectal muscle

The effects of electrical field stimulation and of purine compounds, adenosine and adenosine-5'-triphosphate (ATP) were examined on the mouse isolated rectum. Electrical field stimulation induced frequency-dependent contractions of mouse rectal muscles which were potentiated by physostigmine and inhibited by atropine or tetrodotoxin. Contractile amplitude at 37 degrees C was significantly (P less than 0.05) greater than at 25 degrees C, but the degree of potentiation by physostigmine was significantly (P less than 0.05) greater at 25 degrees C. ATP (1.6 x 10(-4)-1.28 x 10(-3) M) and adenosine (1.8 x 10(-4)-1.48 x 10(-3) M) inhibited in concentration-related fashion contractile responses induced by KCl (1.34 x 10(-2) M-1.07 x 10(-1) M) by acetylcholine (2.2 x 10(-7) M-1.4 x 10(-5) M) and by CaCl2 in high KCl (120 mM)-CaCl2-free Tyrode solution. Theophylline and quinidine ('purinoceptor' antagonists) antagonized ACH contractile effects and so could not be satisfactorily employed in the characterization of the purine receptors in the mouse rectum. It may be concluded from this study that in the mouse rectum, acetylcholine is an excitatory neurotransmitter and that there is a non-adrenergic, non-cholinergic inhibitory neuromuscular transmission in this tissue. Further, ATP and adenosine have been demonstrated to cause relaxation in this tissue by possibly a post-synaptic mechanism involving inhibition of Ca2+ influx into the depolarized muscle.