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1.
平滑肌对一些酸碱等化学物质较为敏感,其可能会影响小肠的肌电活动,进而影响小肠的运动。本研究试图探讨氢氧化钠(Na OH)、盐酸(HCl)、氯化钡(Ba Cl_2)对离体家兔小肠段平滑肌收缩功能的影响,以期了解不同化学药物对小肠肌电活动的影响,为肠道疾病的诊断和治疗提供参考。本研究选取健康家兔,处死后取家兔的十二指肠、空肠、回肠离体后进行恒温灌流,分别给予1 mol/L的Na OH溶液、1 mol/LHCl溶液、1 mol/L Ba Cl_2溶液,并选择相对应肠段作为对照组,仅给予等量生理盐水恒温灌流,对比各组小肠平滑肌电活动变化。研究表明,Ba Cl_2干预下,十二指肠、空肠、回肠的收缩频率均高于对照组、Na OH组、HCl组,差异均具有统计学意义(p0.05);Ba Cl_2组、Na OH组、HCl组离体家兔小肠平滑肌的最大振幅均显著的高于对照组(p0.05),Ba Cl_2组离体家兔小肠平滑肌的最大振幅均显著的高于Na OH组、HCl组(p0.05);Ba Cl_2组、Na OH组离体家兔小肠平滑肌的负波最大振幅均显著的高于对照组、HCl组(p0.05),Ba Cl_2组离体家兔小肠平滑肌的负波最大振幅均显著的高于Na OH组(p0.05)。我们的研究初步表明:Ba Cl_2能显著的增强离体家兔小肠段平滑肌收缩功能,Na OH和HCl溶液会增强体家兔小肠平滑肌的最大振幅。研究显示Ba Cl_2的作用机制可能是促使平滑肌强直性收缩,而Na OH和HCl酸碱类物质的刺激可使肠壁内神经元兴奋,促进小肠平滑肌的运动。  相似文献   

2.
银杏叶提取物对小鼠离体小肠平滑肌收缩特性的影响   总被引:2,自引:0,他引:2  
目的观察不同浓度的银杏叶提取物(Extract of Ginkgo biloba, EGb)对小鼠离体小肠平滑肌活动的影响,探讨EGb对小肠平滑肌的作用机制.方法制备离体肠段标本,灌流给药后记录不同浓度EGb作用下小肠收缩变化.结果低浓度和中浓度的EGb对离体小肠平滑肌有兴奋作用,随浓度增加,低浓度EGb的兴奋程度呈降低趋势,中浓度EGb的兴奋程度呈升高趋势;高浓度EGb引发抑制效应,随浓度增加,抑制程度降低.结论不同浓度范围的EGb对离体小肠平滑肌有不同作用,可能通过对平滑肌的直接作用或调节激素释放,影响离子通道等途径发挥作用.  相似文献   

3.
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。  相似文献   

4.
目的:观察大黄素(emodin)对大鼠离体空肠平滑肌收缩功能的影响,并探讨其作用机制。方法:大鼠离体空肠标本随机分为7组(n=6):对照组,大黄素剂量组(1,5,10,20μmol/L),普萘洛尔(PRO)加大黄素组,格列苯脲(GLI)加大黄素组,NG-基-L厂精氨酸甲酯(1.NAME)加大黄素组,无钙K-H液对照组及无钙K-H液大黄素组。采用颈椎离断法处死大鼠并分离其空肠,将肠段标本与张力换能器相连并置于氧饱和的K-H液中。采用BL-420E+生物信号采集处理系统记录大鼠空肠平滑肌的收缩张力(TE),幅度(AM)和频率(FR)的影响。结果:①大黄素能使大鼠离体空肠平滑肌的收缩张力和幅度明显下降,且呈剂量依赖性(P〈0.05,P〈0.01);对频率无明显影响。②普萘洛尔(P〈0.05)、格列苯脲(P〈0.01)可部分阻断大黄素对空肠平滑肌的抑制作用。③L.NAME对大黄素所引起的空肠平滑肌的抑制作用无影响。④氯化钙所引起的空肠平滑肌收缩可被大黄素所抑制(P〈0.01)。结论:大黄素能明显减弱大鼠离体空肠平滑肌的收缩张力和收缩幅度,对收缩频率无影响。这种作用可能是通过兴奋肾上腺素8受体、兴奋ATP敏感钾通道、阻断细胞膜上钙离子通道实现。  相似文献   

5.
目的 :探讨磁处理党参药液对离体兔小肠平滑肌收缩活动的影响。方法 :通过正常台氏液对照组与磁处理党参药液实验组 ,以及磁处理党参药液组与非磁处理党参药液组进行比较 ,观察对离体兔小肠平滑肌的作用 ,同时观察药液对氯化钡引起离体兔小肠平滑肌收缩活动的影响。结果 :低浓度 ( 5 %、1 0 %、2 0 % )磁处理党参药液对离体兔小肠有轻度抑制作用 ;浓度加大 ( 4 0 %、60 % ) ,有明显促进作用 (P <0 .0 1 ) ;当浓度为 1 0 0 % ,药液有强烈的抑制作用 ,波形几乎呈直线。磁处理药液能解除Bacl2 引起的痉挛性收缩。磁处理与非磁处理党参药液组比较 ,只有浓度 5 %的波幅明显下降 (P <0 .0 1 ) ,其余浓度均无差异显著 (P>0 .0 5 ) ;结论 :磁处理党参药液对小肠平滑肌的收缩活动有明显影响  相似文献   

6.
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。  相似文献   

7.
目的:本研究采用小鼠离体十二指肠平滑肌观察姜黄素对胃肠道蠕动的影响,探讨其作用机制。方法:取小鼠离体十二指肠平滑肌条,放入37℃Krebs液浴槽中,通入95%氧气和5%二氧化碳混合气体,分组进行下列实验:对照组和分别加入10-40 M姜黄素组,测量记录十二指肠平滑肌的自主收缩变化;另取一组平滑肌条,分对照组、乙酰胆碱组、乙酰胆碱+姜黄素组、阿托品组、阿托品+姜黄素组,采用张力换能器连接多通道生理信号采集处理系统,测量比较十二指肠平滑肌舒缩的变化。结果:小鼠十二指肠平滑肌加入姜黄素孵育后,其自主收缩幅度有明显下降(P0.01),而且降低的幅度与姜黄素剂量相关;给与乙酰胆碱引起十二指肠收缩后,再加姜黄素孵育,十二指肠平滑肌的收缩幅度明显的下降(P0.01);给予阿托品引起小鼠平滑肌舒张后,再给予姜黄素孵育,平滑肌收缩幅度进一步降低。结论:姜黄素对小鼠离体十二指肠平滑肌具有直接舒张作用。  相似文献   

8.
目的:观察三七总皂苷对家兔离体小肠平滑肌收缩活动的影响,并探讨其作用机制。方法:取健康家兔,雌雄不拘,将小肠离体后恒温灌流,观察三七总皂苷对家兔小肠自发收缩活动的影响;在灌流液中分别加入BayK8644、左旋硝基精氨酸甲酯(L-NAME)后再加入三七总皂苷,研究其作用机制;在无钙台式液中加入rynodine后再加入三七总皂苷,研究其作用机制。结果:三七总皂苷剂量依赖性的抑制家兔离体小肠平滑肌收缩的幅度。BayK8644和L-NAME均可完全阻断三七总皂苷对家兔小肠平滑肌收缩活动的抑制作用。在无钙台式液中,三七总皂苷显著抑制rynodine引起的细胞内钙收缩活动。结论:三七总皂苷显著抑制家兔小肠平滑肌的收缩活动,其抑制收缩活动机制可能是:增加小肠平滑肌NO浓度,从而抑制细胞外钙内流和内钙释放。  相似文献   

9.
目的观察纳豆枯草杆菌培养滤液(culture filtrate,CF)对家兔离体肠平滑肌的作用,并初步探讨其作用机制。方法制备兔离体回肠标本,分别记录肠平滑肌的正常收缩张力和收缩频率作为给药前对照,然后按累积剂量分别加入CF小剂量(每次0.2mL)、CF大剂量(每次0.5mL)、肉汤(每次0.5mL),给药间隔3min,共给药8次,并描记收缩曲线。观察不同剂量cF对肠平滑肌的作用。另取肠段按毛果芸香碱、CF或阿托品、再毛果芸香碱的顺序给药,观察CF对M胆碱受体的作用。结果CF小剂量组在累积给药达1.6mL时,CF大剂量组在累积给药达3.5mL和4.0mL时,兔离体肠平滑肌收缩张力下降,与给药前比较差异有统计学意义(P〈0.05),其余各点差异均无统计学意义(P〉0.05)。CF小剂量组在累积给药达1.2、1.4、1.6mL时,CF大剂量组在累积给药达4.0mL时,兔离体肠平滑肌收缩频率明显降低,与给药前比较差异有统计学意义(P〈0.05或P〈0.01),其余各点差异均无统计学意义(P〉0.05)。CF或阿托品可明显对抗毛果芸香碱引起的兔离体肠平滑肌收缩张力的增加(P〈0.05或P〈0.01),同时CF还能使其收缩频率明显减少(P〈0.01)。结论纳豆枯草杆菌CF能明显抑制兔离体肠平滑肌蠕动,其作用机制可能与阻断M胆碱受体有关。  相似文献   

10.
目的:观察胆汁对兔离体小肠平滑肌的影响并初步探讨其作用机制.方法:取兔空肠纵行肌条,安置在各恒温灌流肌槽中并用BL-310生物技能实验系统记录空肠平滑肌条的收缩活动.结果:胆汁显著降低兔空肠肌条张力, 减小其收缩波平均振幅及收缩频率,并有剂量依赖关系.结论:胆汁对空肠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.  相似文献   

11.
Interrelationship between the motility of the small intestine and the intensity of energy formation in its smooth muscle layer was studied. The hexokinase activity was found to be significantly higher in the muscle layer of the duodenum as compared to that activity in the ileum and jejunum. No statistically significant differences in the hexokinase activity were revealed between the ileum and jejunum. The results obtained showed hexokinase activity to be highly variable, these values directly correlating with the motor activity of the intestinal muscle layer, representing the contractile apparatus of the intestine.  相似文献   

12.
Naloxone-dependent effects of Met-enkephalin (10(-8) M) on the spontaneous and electrically induced mechanical activities were studied in longitudinal and circular preparations isolated from the cat duodenum, jejunum and ileum. Met-Enkephalin changed the spontaneous activity of all preparations tested with the exception of the circular preparations from the ileum. Met-Enkephalin-induced responses of the longitudinal preparations from the ileum were abolished by treatment with tetrodotoxin (10(-7) M), while the responses of both longitudinal and circular preparations from the duodenum and jejunum were only partially depressed, being resistant to tetrodotoxin components. The latter were most pronounced in the duodenum. The neurogenic electrically induced (0.5 msec, 5 Hz, 150 pulses) responses of all the preparations consisted mainly of contractile components which were significantly and naloxone-dependently reduced by Met-enkephalin (10(-8) M). The contractile components of the responses, which were reduced by Met-enkephalin, were entirely abolished by atropine (3 x 10(-6) M). Both Met-enkephalin and atropine inhibitory effects on the neurogenic responses were more pronounced in the ileum. Met-Enkephalin was found in nerve fibers of the myenteric plexus distributed mainly among the circular muscle. Single immunoreactive nerve fibers were observed in the longitudinal muscle layer of the duodenum but not in the jejunum and ileum. The distribution of Met-enkephalin-like immunoreactivity along the small intestine did not show significant differences among the three intestinal regions tested. The results obtained suggest that Met-enkephalin can modulate the mechanical activity of the cat small intestine, inhibiting cholinergic transmission and/or activating smooth muscle opioid receptors.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

13.
The pharmacology of ethylenediamine (EDA) actions in the rat small intestine was examined using isolated gut-bath preparations of proximal segments of the duodenum, jejunum, and ileum. EDA evoked concentration-dependent tetrodotoxin-insensitive relaxations of the intestine, evidently by direct action on the muscularis. Such actions were simultaneous on the longitudinal and circular muscle layers. Investigation of EDA actions on the circular muscle showed that EDA actions were unrelated to any intrinsic GABAergic mechanisms. Moreover, EDA interacted with muscle sites distinct from ATP, histamine, bradykinin, muscarinic, and adrenergic receptors. The ability of EDA to relax the intestinal musculature was generally greater than the smooth muscle relaxant papaverine and substantially better than nicotinic stimulation of the intrinsic inhibitory neurones. It would appear that EDA may be useful as a direct acting smooth muscle relaxant for the study of the physiology-pharmacology of the rodent small intestine.  相似文献   

14.
The effect of calcitonin gene-related peptide (CGRP) on the cholinergically mediated twitch contraction in longitudinal muscle strips of the small intestine (duodenum, jejunum, ileum) of guinea-pig, pig and man was investigated. Independently of the anatomical region, CGRP inhibited the twitch response in the different specimens of all three species by about 40% with similar IC50 values (1.5-2.4 nmol/l). Only in the guinea-pig small intestine CGRP induced a contraction of the smooth muscle which was sensitive to scopolamine and tetrodotoxin. The electrically evoked [3H]acetylcholine release from jejunal longitudinal muscle strips with myenteric plexus attached of the guinea-pig, which were incubated with [3H]choline, was concentration-dependently inhibited by CGRP. A direct relaxant effect of CGRP on smooth muscle tone of carbachol precontracted preparations was only observed in specimens of the guinea-pig. In conclusion, presynaptic inhibitory CGRP receptors on cholinergic neurones modulate the release of acetylcholine in different parts of the small intestine.  相似文献   

15.
Vasoactive intestinal peptide (VIP) is found in the enteric nervous system of all layers of the small intestine. In the gastrointestinal tract, VIP receptors coupled to adenylate cyclase are present on epithelial, smooth muscle and possibly mononuclear cells. This study analyzes the distribution of VIP binding using in vitro autoradiographic techniques. VIP binding was present in high density in the mucosal layer of rabbit duodenum, jejunum and ileum. Low VIP binding was noted over the smooth muscle layers or the lymphoid follicles. Similar results were obtained in rat small intestine. The density of VIP binding was greatest in duodenal mucosa but was present in lower density in jejunal and ileal mucosa. Again, low VIP binding was noted in the smooth muscle layers or lymphoid follicles. Thus, autoradiographic maps of small intestine indicate that VIP receptors are found primarily in the small intestinal mucosa.  相似文献   

16.
A protein (bovine serum albumin: BSA) and a peptide (luteinizing hormone releasing hormone: LHRH) were used to evaluate proteolytic activity in the intestine of common brushtail possums (Marsupiala, Trichosurus vulpecula). Luminal and mucosal extracts were isolated from the duodenum, jejunum, ileum, caecum, proximal colon and distal colon, their protein content assessed and specific activities in metabolising LHRH and BSA determined in vitro. The degradation of LHRH by luminal extracts was compared with that by the pancreatic enzymes, chymotrypsin, trypsin, and elastase. The protein concentration (microg x mg-1) of mucosal extract in the duodenum was higher ( P<0.05) than in the proximal colon, but that of luminal extracts did not differ significantly between regions. Proteolytic activity of luminal extracts was greater ( P<0.01) in the jejunum and ileum than in the hindgut. In the small intestine, proteolytic activity of luminal enzymes far exceeded that of mucosal enzymes ( P<0.05). All three pancreatic enzymes hydrolysed LHRH, but chymotrypsin had the greatest activity. This study has demonstrated that, in possums, proteolysis occurs primarily in the small intestine through luminal enzymes, with chymotrypsin playing a major role. The possum hindgut contributes little to the metabolism of peptides and proteins, identifying it as a potential site to target for their absorption following oral delivery.  相似文献   

17.
The small intestine of 15- to 33-day-old rats was cut into four segments: duodenum, proximal jejunum, distal jejunum, and ileum. Neutral glycosphingolipids and gangliosides were purified from each segment and analyzed by thin-layer chromatography in order to study the developmental appearance of adult-type glycolipids at each level of the small intestine. Type 1 A-6 glycolipid was first detected in the ileum at 15 days and subsequently in the jejunum and duodenum at 19 days of age. N-Glycolylneuraminic acid was expressed first in the ileum at 17 days, then in the proximal jejunum at 21 days, but only after 29 days in the duodenum. In each region, 6-8 days were required between first detection and full expression of N-glycolylneuraminic acid. The presence of 2-hydroxylated fatty acids in glucosylceramide was found first in the ileum at 19 days, 2-3 days before appearing in the duodenum and proximal jejunum. A period of 2-3 days was necessary to reach full adult-type level of 2-hydroxylated fatty acids in glucosylceramide. These results show that adult-type glycolipids appear earlier in the distal than in the proximal region of the rat small intestine, and that different glycolipids appear at different times and at different rates. The finding that the biochemical differentiation of the whole small intestine expands over a period of 3 days to 2 weeks, depending on the region and the glycolipid, before being fully completed indicates that, in addition to the time lag observed between the distal and the proximal region, the new cells arising from the crypt of Lieberkhün after 15 days of age are not at once fully differentiated.  相似文献   

18.
Modelling slow wave activity in the small intestine   总被引:3,自引:0,他引:3  
We have developed an anatomically based model to simulate slow wave activity in the small intestine. Geometric data for the human small intestine were obtained from the Visible Human project. These data were used to create a one-dimensional finite element mesh of the entire small intestine using an iterative fitting procedure. The electrically active components of the intestinal walls were modelled using a modified Fitzhugh-Nagumo cell model embedded within a longitudinal smooth muscle layer and a layer containing Interstitial Cells of Cajal. Within these layers, the monodomain equation was used to describe slow wave propagation. To solve the monodomain equation, a high-resolution finite difference grid, with an average spatial resolution of 0.95 mm, was embedded within each finite element. The resulting simulations of intestinal activity agree with the experimental observation that slow wave frequency gradually declines from 12 cycles per minute (cpm) in the duodenum to 8 cpm at the terminal ileum. Furthermore, the simulations demonstrated a decrease in conduction velocity with distance along the small intestine (10.7 cm/s in the duodenum, 5.1cm/s in the jejunum and 1.4 cm/s in the ileum), matching experimental recordings from the canine small intestine. We conclude that the framework presented here is capable of qualitatively simulating normal slow wave activity in an anatomical model of the small intestine.  相似文献   

19.
Abstract

We investigated the effect of dietary supplementation of sodium nitroprusside (SNP), a nitric oxide (NO) donor, and N-nitro-L-arginine methyl ester (L-NAME), a NO inhibitor, on neuronal nitric oxide synthase (nNOS) expression in and motility of small intestinum in broilers. A total of 560, one-day-old Ross 308 hybrid mixed sex broiler chicks were divided randomly into one control and seven treatment groups for a 42 day feeding trial including starter phase (0–21 days) and grower phase (22–42 days). The control group was fed a basal diet and the experimental groups were the fed basal diet supplemented with 25, 50, 100 and 200 mg/kg SNP and 25, 50 or 100 mg/kg L-NAME. Ten chickens from each group were sacrificed to collect samples on days 21 and 42. The expression patterns of nNOS immunoreactivity in nerve fibers were determined by immunohistochemistry. In the contractility studies, longitudinal isolated strips of duodenum, jejunum and ileum were treated with 10?5 M L-arginine and 10?4 M SNP. Immunohistochemistry revealed that nNOS expression was not detectable in the duodenum or ileum of either the control or experimental groups. On the other hand, nNOS immunoreactivity in the jejunum control group showed a strong reaction on day 21, but the reaction was weak on day 42. nNOS expression clearly was suppressed on day 21 by the diet supplemented with L-NAME, while the diet supplemented with SNP stimulated nNOS expression on day 21. Contractility experiments revealed that spontaneous contractility of isolated strips of duodenum, jejunum and ileum showed no significant difference among groups. Spontaneous contractions of all strips were inhibited by L-arginine and SNP in all groups. The percentage inhibition rate of spontaneous contractions of jejunum application on days 21 and 42 after L-arginine decreased in the group supplemented with 100 mg/kg L-NAME. The percentage inhibition rate on day 21 after SNP application decreased in both groups that received 50 and 100 mg/kg L-NAME. We demonstrated the expression pattern of nNOS in nerve fibers in jejunum of broiler chickens. Contractility studies revealed that the NOS-NO pathway may play a role in smooth muscle contraction of small intestine of chickens. Feeding strategies that supplement NO donor and NO inhibitor can be of physiological importance to small intestine motility owing to alteration of nNOS expression in the jejunum.  相似文献   

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