传出神经系统药物对小鼠离体十二指肠平滑肌运动的影响

目的通过体外小鼠离体十二指肠平滑肌的试验,观察五种传出神经系统药物对其收缩功能的作用。方法将小鼠离体十二指肠平滑肌置于模拟内环境中,采用BL-420生物机能系统观察模拟的内环境因素发生变化时,离体十二指肠平滑肌运动的变化,当分别加入几种传出神经系统药物后,平滑肌的收缩运动是否会受到不同程度的影响。结果肾上腺素、阿托品可使平滑肌收缩活动减小,抑制平滑肌的收缩力;水杨酸毒扁豆碱、毛果芸香碱、乙酰胆碱使平滑肌收缩活动加大,可加强平滑肌的收缩力。结论传出神经系统药物影响小鼠离体十二指肠平滑肌运动。     

焦山楂醇提物对大鼠离体胃、肠平滑肌条收缩性的影响

目的:观察焦山楂醇提取液对大鼠离体胃、肠平滑肌的影响.方法:本研究以大鼠的离体胃、肠平滑肌条为模型,观察在正常克氏液条件下加入焦山楂醇提取液后大鼠胃、肠平滑肌条收缩状况.同时观察乙酰胆碱、阿托品作用下加入焦山楂提取液对大鼠胃、肠平滑肌运动的影响.结果:焦山楂醇提取液在4-8 mg生药/ml浓度范围内可显著抑制大鼠胃、肠平滑肌条的运动,且具有明显剂量依赖性.焦山楂醇提取液(8mg生药/ml)可拮抗乙酰胆碱引起的胃肠平滑肌的强烈收缩和阿托品引起的肠平滑肌的舒张作用.结论:焦山楂醇提取液对大鼠胃、肠平滑肌条的收缩具有明显的抑制作用.     

山楂醇提取物对大鼠离体胃、肠平滑肌条收缩性的影响

目的:考察山楂醇提取液对大鼠离体胃、肠平滑肌的影响.方法:本研究以大鼠的离体胃、肠平滑肌条为模型,考察在正常克氏液条件下加入山楂提取液大鼠胃、肠平滑肌条收缩状况.同时观察乙酰胆碱、阿托品作用下加入山楂提取液大鼠肠平滑肌条收缩状况.结果:山楂醇提取液在5-20mg生药/ml浓度范围内可显著抑制大鼠胃、肠平滑肌条的运动,且具有明显剂量依赖性.山楂醇提取液(20mg生药/ml)可拮抗乙酰胆碱引起的胃肠平滑肌的强烈收缩,山楂醇提取液(20mg生药/ml)可对抗阿托品引起的肠平滑肌的舒张作用.结论:山楂醇提取液对大鼠胃、肠平滑肌条的收缩具有明显的抑制作用.     

化学药物对家兔离体小肠平滑肌电生理特性的影响

观察各种化学药物对家兔离体小肠各段平滑肌的作用,采用常规离体灌流的十二指肠、空肠及回肠平滑肌标本作舒缩运动实验,记录用药前后各段小肠平滑肌的收缩活动特征及变化规律.结果显示：不同浓度的乙酰胆碱和磷酸组织胺能增强小肠各段平滑肌的收缩频率与幅度,其幅值变化与用药前有显著性差异（P＜0.01） ,并呈剂量依赖性;而不同浓度的肾上腺素和阿托品则抑制小肠各段平滑肌（P＜0.01） .不同肠段对各种化学药物的作用存在着差异,一般十二指肠作用最强,空肠次之,回肠最差.     

氢溴酸高乌甲素对小肠平滑肌运动的作用

目的：研究氢溴酸高乌甲素对小肠平滑肌运动的影响并探讨其可能的作用机制。方法：记录氢溴酸高乌甲素对家兔离体小肠平滑肌运动的影响,并测定氢溴酸高乌甲素处理后小鼠小肠推进运动的变化。结果：氢溴酸高乌甲素抑制家兔离体小肠平滑肌收缩的发展张力。纳洛酮对氢溴酸高乌甲素的肠肌抑制作用无明显影响（P〉0.05）。乙酰胆碱（0.1 mg/L）可使家兔小肠舒张末张力明显增加。氢溴酸高乌甲素处理后,乙酰胆碱对肠肌舒张末张力的增加百分比降低（P〈0.05）。氢溴酸高乌甲素对小鼠小肠推进运动有显著抑制作用（P〈0.05）。结论：氢溴酸高乌甲素对小肠平滑肌收缩有抑制作用,并可以部分阻断乙酰胆碱的肠肌收缩作用,阿片受体可能不参与该抑制作用。     

ERK1/2参与自发性高血压大鼠离体血管环对apelin-13舒张反应性降低作用

研究自发性高血压大鼠(spontanously hypertensive rat,SHR)离体血管环对G蛋白偶联受体APJ的内源性配体apelin-13的血管收缩与舒张反应及其与一氧化氮(NO)和ERK1/2通路关系．采用离体血管环体外灌流方法用Power-Lab生物信息采集仪检测血管环的张力．实验分组如下：新福林(Phenylephrine,PE)组,乙酰胆碱(acetylcholine,Ach)组,apelin-13组,apelin-13 + PE组,apelin-13 + Ach组,PD98059(ERK1/2抑制剂) + PE组,PD98059 + Ach组,LNNA(L-nitro-arginine,硝基左旋精氨酸,一氧化氮合酶抑制剂) + PE组,LNNA+Ach组,apelin-13(预孵育) + PD98059 + PE组,apelin-13(预孵育)+PD98059+ Ach组,apelin-13(预孵育) + LNNA + PE组和apelin-13(预孵育) + LNNA + Ach组,以WKY大鼠血管环为对照组．培养大鼠血管平滑肌细胞,Western blot检测ERK1/2蛋白表达．结果显示：a．apelin-13对于有内皮的血管表现出浓度依赖性舒张作用,血管舒张百分比SHR < WKY大鼠,而对于去除内皮血管,apelin-13则表现出收缩血管的作用,且收缩张力SHR>WKY大鼠,apelin-13预孵育,能减少SHR和WKY大鼠血管对新福林的缩血管反应性,增加对乙酰胆碱的舒张反应性;b．NOS抑制剂LNNA阻断NO形成后,血管环对apelin-13的舒张反应明显抑制,且SHR组较WKY组对apelin的舒张反应减少更明显,提示apelin-13的舒血管效应至少部分依赖NO通路,而SHR高血压大鼠NO通路障碍减弱了apelin对血管的舒张作用;c．ERK1/2抑制剂PD98059预孵育后血管环对apelin-13表现出浓度依赖性的收缩,与去除内皮后apelin-13的收缩血管效应趋势一致,血管收缩张力SHR＞WKY大鼠,PD98059逆转了apelin-13引起的血管舒张效应;d．Apelin-13促大鼠VSMCs ERK1/2磷酸化增加并呈剂量依赖性和时间依赖性,ERK1/2抑制剂PD98059可以减少apelin-13诱导ERK1/2的磷酸化．结果表明,自发性高血压大鼠离体血管环对apelin-13舒张反应性降低, NO通路和ERK1/2通路介导了apelin-13的舒张血管作用．     

玉郎伞提取物对支气管平滑肌舒张作用的研究

研究玉郎伞水提物及从玉郎伞中提取纯化的三种活性成份—黄酮、皂苷、多糖对豚鼠离体气管条的舒张作用。实验制备新鲜豚鼠离体气管条,在克氏缓冲液中分别加入组胺或乙酰胆碱,使豚鼠气管螺旋条收缩达高峰后观察不同剂量的玉郎伞水提物及三种活性成份对乙酰胆碱或组胺致气管条收缩的影响。结果表明,玉郎伞水提物及皂苷、多糖能对抗乙酰胆碱或组胺对豚鼠离体气管条的收缩作用,使组胺及乙酰胆碱量效曲线右移。因此,玉郎伞水提物及皂苷、多糖有较强的支气管舒张作用。     

辣椒素对离体大鼠胃平滑肌收缩性的影响

目的:考察辣椒素对离体大鼠胃平滑肌收缩性的影响。方法:本研究以大鼠的离体胃平滑肌条为模型,首先考察在正常钙克氏液、高钙克氏液和低钙克氏液中辣椒素对胃平滑肌收缩作用的影响。然后正常克氏液中,分别观察辣椒素对乙酰胆碱、新斯的明、阿托品分别存在下的胃平滑肌收缩性的影响。结果:辣椒素在2.5μmol/L-40μmol/L浓度范围内可剂量依赖性显著抑制高钙溶液(Ca2 终浓度5μmol/L)引起的大鼠胃平滑肌强烈收缩,在5μmol/L-40μmol/L浓度范围内可显著抑制正常克氏液中大鼠胃平滑肌条的运动,且具有明显剂量依赖性,在10μmol/L-40μmol/L浓度范围内可显著抑制低钙克氏液中大鼠胃平滑肌条的运动,且具有剂量依赖性。辣椒素(10μmol/L)可拮抗乙酰胆碱和新斯的明引起的收缩作用(P<0.01)。辣椒素(10μmol/L)的作用与阿托品具有相加作用(P<0.01)。结论:辣椒素对胃平滑肌的收缩具有明显的抑制作用。     

黄芩苷对家兔离体子宫平滑肌的作用

目的:观察黄芩苷对家兔离体子宫平滑肌收缩的作用及其与Ca2+的关系.方法:制作常规离体家兔子宫平滑肌肌条,考察黄芩苷对子宫肌条反应的影响.结果:(1)黄芩苷(5-10mmol-L-1)剂量依赖抑制子宫平滑肌收缩;(2)黄芩苷对催产素及高K去极化液中Ca2+所致的离体子宫平滑肌收缩均呈剂量依赖性抑制;使CaC12累积量-效曲线非平行性右移,最大效应下降,呈非竞争性抑制;(3)且对子宫平滑肌依细胞内、外Ca2+两种收缩成分均呈抑制作用.结论:黄芩苷对家兔离体子宫平滑肌条的抑制作用,可能与其拮抗Ca2+有关.     

CYP4A抑制剂HET0016对小鼠离体主动脉血管张力的影响

为研究CYP4A抑制剂HET0016对小鼠离体主动脉血管张力的影响,对雄性C57BL/6J小鼠进行脱臼处死后,取主动脉并剪成3~4 mm长的血管环,固定于微血管测定仪的浴槽内,分别用高钾溶液(KCl 60 mmol/L)和去氧肾上腺素(Phe 1μmol/L)进行血管功能性检测,发现二者均能让离体主动脉环产生持续性收缩;然后采用累积给药法观察1μmol/L Phe处理组、60 mmol/L高钾处理组、eNOS抑制剂L-NAME(100μmol/L)和L-钙通道阻滞剂nifedipine(1μmol/L)单独或共同孵育后Phe(1μmol/L)预收缩处理组中不同浓度HET0016对小鼠离体主动脉环张力的影响,并探讨其可能的作用机制。结果发现,高浓度的HET0016可以舒张高钾和Phe预收缩的内皮完整的主动脉环;对于L-NAME单独孵育后Phe预收缩的内皮完整的主动脉环,只有高浓度的HET0016有显著舒张作用;而对于nifedipine单独孵育以及L-NAME和nifedipine共同孵育后Phe预收缩的主动脉环,HET0016的舒张作用呈明显的浓度依赖性。这些结果显示,HET0016这种舒张作用是多通道的,呈部分的内皮依赖性,但也不是主要通过L-电压门控钙通道产生,只有在高浓度的情况下才开始影响L-电压门控钙通道。     

Morinda lucida reduces contractility of isolated uterine smooth muscle of pregnant and non-pregnant mice.

The present work investigated the effect of Morinda lucida (M. lucida) extract on isolated uterine smooth muscle of pregnant and non-pregnant mice. Pregnant and non-pregnant mice were pretreated with oral stilboesterol (0.1 mg/kg body weight) and killed by cervical dislocation. Thin strips of the uterus were cut and mounted in a 20ml organ bath containing De Jalon solution bubbled with 95%O2-5% CO2 gas mixture. The strips were connected to a force transducer coupled to a Grass 7D Polygraph for the recording of isometric tension. Effects of graded concentrations of oxytocin (OXY; 10-5-10-2 mol/L), acetylcholine (ACh; 10-9-10-5 mol/L) and M. lucida extract (0.015-1.5 mg/ml) were recorded. Fresh uterine strips were then incubated with M. lucida extract for 5mins and cumulative response to OXY was repeated. Another set of fresh strips was incubated in L-NAME for 15mins and the cumulative responses to M.lucida extract were repeated. OXY resulted in increased contractile responses in both pregnant and non-pregnant uterine muscles. M. lucida resulted in relaxation of the uterine smooth muscle in both pregnant and non-pregnant mice at all doses. However, at 1.5mg/ml, M. lucida completely blocked spontaneous uterine contractions. Following incubation with L-NAME, M. lucida extract led to a slightly greater relaxation of the uterine strips. In conclusion, M. lucida reduced contractility of uterine smooth muscle in both pregnant and non-pregnant mice as well as blocking contractile responses to OXY and Ach in uterine smooth muscle of pregnant and non-pregnant mice. There was no significant alteration of M. lucida activity by L-NAME suggesting that the action of the compound on uterine muscle is not associated with impaired nitric oxide synthase.     

Effects of some autonomic drugs and neuropeptides on the mechanical activity of longitudinal and circular muscle strips isolated from the carp intestinal bulb (Cyprinus carpio)

1. The mechanical responses to some autonomic drugs and neuropeptides of longitudinal muscle (LM) and circular muscle (CM) strips isolated from the carp intestinal bulb were investigated in vitro. 2. Acetylcholine and carbamylcholine caused concentration-dependent transient contraction of both LM and CM strips. Tetrodotoxin had no effect, but atropine selectively decreased the contractile responses to acetylcholine and carbamylcholine. 3. Excitatory alpha-2 and inhibitory beta adrenoceptors were present in both LM and CM strips. 4. 5-Hydroxytryptamine (5-HT) caused concentration-dependent contraction of both LM and CM strips. Tetrodotoxin, atropine and methysergide decreased the contractile responses to 5-HT. 5. Some neuropeptides (angiotensin I, angiotensin II, bombesin, bradykinin, neurotensin, somatostatin and vasoactive intestinal polypeptide) did not cause any mechanical response (contraction or relaxation) in either smooth muscle strip. 6. Substance P (SP), neurokinin A (NKA) and neurokinin B (NKB) caused contraction of both LM and CM strips. However, the time course of the contraction in LM was different from that in CM. The order of potency was NKA greater than SP greater than NKB in LM strips and NKA greater than SP much greater than NKB in CM strips. In LM strips, the contractile responses to tachykinins were unaffected by spantide and methysergide, but partly decreased by tetrodotoxin and atropine. On the other hand, the contractile responses of CM strips were unaffected by tetrodotoxin, atropine, methysergide and spantide. 7. Dynorphin (1-13) (DYN), leucine-enkephalin (L-Enk) and methionine-enkephalin (M-Enk) caused concentration-dependent contraction of both LM and CM strips. The order of potency was DYN greater than M-Enk greater than L-Enk. Naloxone selectively decreased the responses to opiate peptides. 8. The present results indicate that acetylcholine, carbamylcholine, catecholamines, 5-HT, tachykinins (SP, NKA and NKB) and opiate peptides (DYN, L-Enk and M-Enk) affect the mechanical activity of LM and CM strips isolated from the carp intestinal bulb through their specific receptors.     

缩胆囊素和促胰液素对豚鼠离体胃平滑肌运动的影响

用８个肌槽同时记录豚鼠胃不同部位肌条的收缩活动,以观察八肽缩胆囊素（ＣＣＫ－８）和促胰液素的影响。结果表明：ＣＣＫ－８能（１）增高各部位纵行肌和环行肌的张力;（２）加快胃体纵行肌,胃窦纵行肌、环行肌和幽门环行肌的收缩频率;（３）增大胃窦环行肌收缩波平均振幅和（４）增加幽门环行肌收缩波运动指数,但减少胃体和胃窦纵行肌收缩波平均振幅。上述作用均不能被阿托品和消炎病所阻断。而促胰液素对各部位肌条的收缩活动没有明显的影响。     

Nerves containing substance P,vasoactive intestinal polypeptide,enkephalin or somatostatin in the guinea-pig taenia coli

Summary The guinea-pig taenia coli is rich in peptide-containing nerves. Nerve fibres containing substance P (SP), vasoactive intestinal peptide (VIP), or enkephalin, were numerous in the smooth muscle while somatostatin fibres were very few. Nerve fibres displaying SP or VIP immunoreactivity were numerous in the myenteric plexus. Enkephalin nerve fibres were fairly numerous in the plexus while somatostatin nerve fibres were sparse. Nerve cell bodies containing immunoreactive SP or VIP were regularly seen in the plexus. Delicate varicose elements of the different types of nerve fibres were found to ramify around nerve cell bodies in a manner suggestive of innervation.In the electron microscope the various peptide-storing nerve fibres (i.e., elements containing SP, VIP or enkephalin) were found to contain a varying number of fairly large, electron-opaque vesicles in the varicose swellings. These vesicles represent the storage site of the neuropeptides.The isolated taenia coli responded to electrical nerve stimulation with a contraction. After cholinergic and adrenergic blockade the contractile response was replaced by a relaxation followed by a contraction upon cessation of stimulation. SP contracted the taenia while VIP caused a relaxation. The enkephalins raised the resting tension slightly while somatostatin had no effect. These observations are compatible with a role for SP as an excitatory neurotransmitter and for VIP as an inhibitory one, and with the view that both SP neurones and VIP neurones act as motor neurones. In preparations contracted by SP the electrically induced contractions were reduced in amplitude while the electrically induced relaxations seen after adrenergic and cholinergic blockade were enhanced in amplitude. In preparations relaxed by VIP there was an increased contractile response to electrical stimulation, while in the atropine + guanethidine-treated preparation the electrically induce relaxations were reduced in amplitude. The enkephalins reduced the contractile response to electrical stimulation, while somatostatin induced a very small reduction in the amplitude of such responses. These observations suggest that SP neurones and VIP neurones may play additional roles as interneurones. Somatostatin neurones probably act as interneurones. Enkephalin-containing fibres may serve to modify the release of transmitter from other nerves in the smooth muscle, perhaps through axo-axonal arrangements. Alternatively, the enkephalin nerve fibres in the smooth muscle are afferent elements involved in mediating sensory impulses to the myenteric plexus.     

Downregulation of profilin with antisense oligodeoxynucleotides inhibits force development during stimulation of smooth muscle

The actin-regulatory protein profilin has been shown to regulate the actin cytoskeleton and the motility of nonmuscle cells. To test the hypothesis that profilin plays a role in regulating smooth muscle contraction, profilin antisense or sense oligodeoxynucleotides were introduced into the canine carotid smooth muscle by a method of reversible permeabilization, and these strips were incubated for 2 days for protein downregulation. The treatment of smooth muscle strips with profilin antisense oligodeoxynucleotides inhibited the expression of profilin; it did not influence the expression of actin, myosin heavy chain, and metavinculin/vinculin. Profilin sense did not affect the expression of these proteins in smooth muscle tissues. Force generation in response to stimulation with norepinephrine or KCl was significantly lower in profilin antisense-treated muscle strips than in profilin sense-treated strips or in muscle strips not treated with oligodeoxynucleotides. The depletion of profilin did not attenuate increases in phosphorylation of the 20-kDa regulatory light chain of myosin (MLC20) in response to stimulation with norepinephrine or KCl. The increase in F-actin/G-actin ratio during contractile stimulation was significantly inhibited in profilin-deficient smooth muscle strips. These results suggest that profilin is a necessary molecule of signaling cascades that regulate carotid smooth muscle contraction, but that it does not modulate MLC20 phosphorylation during contractile stimulation. Profilin may play a role in the regulation of actin polymerization or organization in response to contractile stimulation of smooth muscle.     

Influence of variations of Ca++ on responses of segments of the isolated coronary artery to acetylcholine

The effect of external calcium concentration on the Ach-induced contraction of coronary arteries was studied in vitro. It resulted that the effect of Ach was enhanced by the increase, or reduced by the decrease of calcium concentration. It is concluded that, as it was known for the intestinal smooth muscle, also for the smooth muscle of the coronary arteries, the contractile effect of Ach is dependent on the calcium of the medium.     

Epr Spectroscopic Studies of Detection of a Carbon-Centered Free Radical During Acetylcholine-Induced and Endothelium-Dependent Relaxation of Guinea Pig Pulmonary Artery

Vascular smooth muscle relaxation by several vasodilators, including acetylcholine (Ach) and ATP, depends on the presence of intact endothelium. Ach is thought to activate muscarinic receptors on endothelium to release an endothelium-derived relaxing factor (EDRF) which brings about relaxation of smooth muscle. In order to assess the role of free radicals in the endothelium-dependent relaxation of blood vessel, we have studied the effect of a spin-trapping agent, phenyl t-butyl nitrone (PBN). on Ach-, ATP-, and sodium nitroprusside-induced relaxation of guinea pig pulmonary artery. Arterial strips were mounted in a 5-ml organ bath containing Krebs solution equilibrated with 95% O₂ and 5% CO₂ at 37°C. After increasing vascular tone by a synthetic prostaglandin endoperoxide analog (50 ng/ml), the strips relaxed dose-dependently in response to Ach (5 × 10^-8M), ATP (1.5 × 10^-6M) or sodium nitroprusside (6 × 10^-9 M). Removal of the endothelium abolished the relaxation by Ach or ATP, but did not affect the relaxation by sodium nitroprusside. PBN inhibited Ach-induced relaxation of pulmonary artery dose-dependently, but had no effect on relaxations by ATP or sodium nitroprusside. PBN did not block radioligand binding to muscarinic cholinergic membrane receptors on both chick embryonic heart and guinea pig pulmonary artery endothelial cells indicating that it does not block the muscarinic receptors. Spin trapping in combination with electron paramagnetic resonance (EPR) spectral analysis revealed a carbon-centered radical with hyperfine splitting constants of a_N = 16.0 G and a_β^H: = 3.85 G in the lipid extracts of pulmonary artery (0.2-0.4g) incubated with PBN (14mM) and Ach (3 × 10^-6M) for 20min. No signal was detected when endothelium was removed. Our data suggest that the endothelium-dependent relaxation of pulmonary artery by Ach is associated with the generation of a free-radical and can be prevented by a spin-trapping agent. ATP, however, relaxes the arterial smooth muscle by a different mechanism.     

Different responsiveness of excitatory and inhibitory enteric motor neurons in the human esophagus to electrical field stimulation and to nicotine

To compare electrical field stimulation (EFS) with nicotine in the stimulation of excitatory and inhibitory enteric motoneurons (EMN) in the human esophagus, circular lower esophageal sphincter (LES), and circular and longitudinal esophageal body (EB) strips from 20 humans were studied in organ baths. Responses to EFS or nicotine (100 microM) were compared in basal conditions, after N(G)-nitro-l-arginine (l-NNA; 100 microM), and after l-NNA and apamin (1 microM). LES strips developed myogenic tone enhanced by TTX (5 microM) or l-NNA. EFS-LES relaxation was abolished by TTX, unaffected by hexamethonium (100 microM), and enhanced by atropine (3 microM). Nicotine-LES relaxation was higher than EFS relaxation, reduced by TTX or atropine, and blocked by hexamethonium. After l-NNA, EFS elicited a strong cholinergic contraction in circular LES and EB, and nicotine elicited a small relaxation in LES and no contractile effect in EB. After l-NNA and apamin, EFS elicited a strong cholinergic contraction in LES and EB, and nicotine elicited a weak contraction amounting to 6.64 +/- 3.19 and 9.20 +/- 5.51% of that induced by EFS. EFS elicited a contraction in longitudinal strips; after l-NNA and apamin, nicotine did not induce any response. Inhibitory EMN tonically inhibit myogenic LES tone and are efficiently stimulated both by EFS and nicotinic acetylcholine receptors (nAChRs) located in somatodendritic regions and nerve terminals, releasing nitric oxide and an apamin-sensitive neurotransmitter. In contrast, although esophageal excitatory EMN are efficiently stimulated by EFS, their stimulation through nAChRs is difficult and causes weak responses, suggesting the participation of nonnicotinic mechanisms in neurotransmission to excitatory EMN in human esophagus.