奥曲肽对兔Oddi括约肌运动的作用

目的:研究奥曲肽对Oddi括约肌运动的影响.并比较给药途径不同时的作用效应 方法:建立兔Oddi括约肌测压急性实验动物模型.通过静脉灌注和皮下注射药物技术.观察Oddi括约肌运动的变化 结果:静脉灌注或皮下注射奥曲肽3.5μg/kg,连续监测1小时.兔Oddi括约肌基础压以及时相收缩幅度、收缩时限和收缩频率均无明显改变。结论:奥曲肽对兔Oddi括约肌运动无明显作用 奥曲肽经静脉或皮下注射.对括约肌运动的影响无不同效应     

血小板源生长因子对离体大鼠胸主动脉血管张力的影响

目的 :观察血小板源生长因子对主动脉血管环舒缩作用的影响。方法 :采用离体灌流SD大鼠胸主动脉血管环标本 ,观察不同浓度的血小板源生长因子 BB（PDGF BB）对大鼠胸主动脉血管环的舒缩作用的影响 ,并与去甲肾上腺素 （NE）作对比。结果 :PDGF BB对大鼠胸主动脉有明显的收缩作用 ,阈浓度为 2× 10 -10 mol/L ,且呈现出一种浓度依赖关系 ;与NE相比 ,PDGF BB对血管的收缩幅度低于NE ,但其收缩血管的活性高于NE。PDGF BB对去内皮的血管同样产生收缩作用 ,鱼精蛋白可抑制PDGF BB收缩大鼠的胸主动脉的作用。结论 :PDGF BB对大鼠胸主动脉有明显的收缩作用 ,且呈现出一种浓度依赖关系 ,其血管收缩作用为非内皮依赖性收缩作用 ,鱼精蛋白可抑制PDGF BB收缩血管的作用。     

抑制血管紧张素Ⅱ1型受体对自发性高血压大鼠阻力血管节律性振荡舒缩的作用

目的 观察抑制血管紧张素Ⅱ1型受体对自发性高血压大鼠(SHR)阻力血管节律性振荡舒缩的作用.方法 采用小血管张力测量仪测定SHR对照组、替米沙坦[5 mg/(kg·d)]组和咪哒普利[3 mg/(kg·d)]组离体肠系膜上动脉Ⅱ级分支血管环对不同浓度乙酰胆碱、硝酸甘油的反应性及对血管紧张素Ⅱ、去甲肾上腺素诱导的节律性振荡舒缩反应.结果 1)第16周时,替米沙坦组和咪哒普利组鼠尾动脉收缩压明显低于对照组(P＜0.01).2)与对照组相比,替米沙坦和咪哒普利能显著增强SHR肠系膜动脉血管环对乙酰胆碱(10-6～10-4 mol/L)的舒张反应(P＜0.01);替米沙坦,而不是咪哒普利,增强血管环对硝酸甘油(10-5 mol/L)的反应性(P＜0.05).3)替米沙坦,而不是咪哒普利,显著降低血管环对血管紧张素Ⅱ(10-6 mol/L)和去甲肾上腺素(10-5 mol/L)诱导的节律性振荡舒缩反应(P＜0.01).结论 替米沙坦和咪哒普利能显著降低SHR收缩压;替米沙坦可增强SHR肠系膜动脉内皮依赖和非内皮依赖的血管舒张功能,并显著降低SHR肠系膜动脉节律性振荡舒缩反应;咪哒普利虽能改善SHR肠系膜动脉内皮依赖性舒张功能,而对SHR肠系膜动脉节律性振荡舒缩反应无作用.     

去甲肾上腺素和哌唑嗪对自发性高血压大鼠动脉平滑肌细胞膜Ca~(2+)-ATPase活性和PMCA1 mRNA表达的影响

目的 观察去甲肾上腺素及其俚.肾上腺素能受体拮抗剂哌唑嗪对自发性高血压大鼠血管平滑肌细胞Ca~(2+)-ATPasee活性及mRNA表达的影响.方法 采用生化酶学法和逆转录聚合酶链反应技术观察不同浓度去甲肾上腺素和哌唑嗪对自发性高血压大鼠血管平滑肌细胞Ca~(2+)-ATPase活性和mRNA表达的影响.结果 与自发性高血压大鼠组比较,10~(-7)mol/L去甲肾上腺素能减弱Ca~(2+)-ATPase活性(P<0.01)及mRNA的表达(P<0.01),10~(-5) mol/L和10~(-6) mol/L哌唑嗪能减弱10~(-7)moL/L去甲肾上腺素对Ca~(2+)-ATPase活性的抑制作用(P<0.05).10~(-6) mol/L哌唑嗪可抑制10~(-7)mol/L去甲肾上腺素对PMCA1 mRNA表达的影响(P<0.05).单用哌唑嗪对Ca~(2+)-ATPase活性及mRNA表达水平无明显改变(P>0.05).结论 去甲肾上腺素抑制自发性高血压大鼠Ca~(2+)-ATPase活性和下调PMCA1 mRNA表达,可能是通过α_1肾上腺素能受体途径介导基因转录的下调.哌唑嗪可通过阻断α_1肾上腺素能受体途径抑制去甲肾上腺素对自发性高血压大鼠血管平滑肌细胞Ca~(2+)-ATPase活性和PMCA1 mRNA表达的影响.     

小鼠十二指肠运动中NO对NA作用的影响及机制

目的观察去甲肾上腺素(noradrenaline ,NA)对离体小鼠十二指肠肌条收缩幅度及一氧化氮(nitricoxide ,NO)对NA作用的影响;探讨NO和NA之间的关系及影响机制。方法用器官浴槽孵育离体小鼠十二指肠肌条,以肌张力收缩幅度抑制比为指标观察NA对肌条收缩幅度及NO对NA作用的影响。结果NA对肌条的收缩幅度有明显的抑制作用,在浓度1.2×10 -4～1.2×10 -8mol/L范围内,呈剂量-效应关系,其中1.2×10 -8mol/L组与对照组之间无显著性差异(P >0 .0 5 )。L Arg对肌条的收缩幅度有明显的抑制作用,在浓度2×10 -2 ～2×10 -6mol/L范围内,呈剂量-效应关系。除2×10 -6mol/L组外,其余各浓度的L Arg与对照组均有显著性差异(P <0 .0 0 1)。用无反应剂量2×10 -6和2×10 -3 mol/L的L Arg孵育标本后加入NA ,浓度为1.2×10 -5,1.2×10 -6,1.2×10 -7,1.2×10 -8mol/L的NA对肌条收缩幅度的抑制作用明显增强,与单独NA组的作用相比差异有显著性(P <0 .0 0 1) ;而1.2×10 -4mol/LNA组与单独NA组的作用相比差异无显著性(P >0 .0 5 )。分别用一氧化氮合酶(NOS)的抑制剂L NNA、可溶性鸟苷酸环化酶(sGC)抑制剂ODQ、α肾上腺素能受体阻断剂酚妥拉明(phentolamine)均使NA对肌条收缩幅度抑制效应明显减弱,与对照组比较有显著性差异(P <0 .0 0     

加贝酯对Oddi括约肌运动的影响

目的　观察加贝酯对Oddi括约肌运动功能的影响。方法　对我院 12例行内镜下逆行胰胆管造影 (ERCP)患者于内镜下作Oddi括约肌测压术 ,记录Oddi括约肌的基础压、基础收缩幅度、收缩频率和运动指数 (基础收缩幅度×收缩频率 ) ,并在静脉滴注加贝酯 1、3mg·kg-1·h-1前后 ,分别重复以上测压过程。以用药前后记录数据作自身对照配对t检验进行统计学处理。结果　①静脉滴注加贝酯1、3mg·kg-1·h-1不影响Oddi括约肌的基础压 (P >0 .0 5 )和基础收缩幅度 (P >0 .0 5 )。②加贝酯能明显减少Oddi括约肌的收缩频率 (P <0 .0 5 ) ,但用药剂量 1、3mg·kg-1·h-1之间差异无显著性 (P >0 .0 5 )。③大剂量加贝酯可明显降低Oddi括约肌运动指数 (P <0 .0 1) ,且 3mg·kg-1·h-1与 1mg·kg-1·h-1剂量间差异也有显著性 (P <0 .0 5 )。结论　加贝酯能减少人Oddi括约肌的收缩频率 ,3mg·kg-1·h-1时还能降低运动指数。加贝酯对Oddi括约肌运动的影响可解释加贝酯减少ERCP后胰腺炎的发生。     

胆肠吻合与引流对胆道动力的影响

目的：模拟生理性消化期及消化间期神经与体液条件,观察家兔胆肠吻合术前后胆管和Oddi括约肌（SO）动力的变化。方法：将35只家兔随机分为对照组和实验组共5组。实验组则分别静脉注射胆囊收缩素CCK10ng/kg、胃动素受体激动剂红霉素10mg/kg、迷走神经抑制剂阿托品3μg/kg和一氧化氮合成酶抑制剂L－NAME10mg/kg。于家兔十二指肠对系膜缘插孔,经乳头逆行插入测压导管,采用低顺应性毛细管灌注系统测压。每组在测定完成后将胆囊与空肠上段吻合,关腹饲养1周后重复测压。结果：行胆囊空肠吻合术后SO基础压明显增高,而收缩幅度降低,收缩时间缩短,但收缩频率无明显改变。L－NAME、CCK、红霉素均有兴奋SO的作用,分别表现为基础压和收缩幅度、收缩频率的改变。但与吻合前相比,胆囊空肠吻合后增大的幅度降低了。结论：SO的紧张性收缩与自发性收缩均受神经与体液因素的调节,胆囊空肠吻合与引流可引起SO紧张性收缩增强,而使自发性收缩减弱,若对Oddi括约肌功能障碍（SOD）患者施行胆肠吻合术,可能无法缓解临床症状,故应慎重选择其手术方式。     

不同周龄高血压鼠及正常Wistar大鼠主动脉β肾上腺素受体亚型舒张作用的改变

目的 观察4周、12周自发性高血压大鼠(SHR)和正常血压Wistar大鼠主动脉异丙肾上腺素(Iso)、多巴酚丁胺(Dob)、沙丁胺醇(Sal)、SR 58611A舒血管作用的改变.方法 采用离体血管张力实验方法,观察药物对1 μmol/L去氧肾上腺素(PE)预收缩的4周、12周SHR和正常血压Wistar大鼠主动脉收缩的影响.结果 Iso(10-8 mol/L～10-4 mol/L)对主动脉的舒血管作用随年龄增加及血压升高而降低;Dob(10-8 mol/L～10-4 mol/L)的舒张作用在高血压发展过程中逐渐减弱,但是不受血管增龄影响;Sal(10-8 mol/L～10-4 mol/L)的舒张作用在血管增龄及高血压发展过程中逐渐减弱;SR58611A(10-7 mol/L～10-4 mol/L)的舒张作用在血管增龄及高血压发展过程中无显著性变化.结论 在血管增龄及高血压发展过程中,不同β肾上腺素受体亚型舒张作用的变化不同.     

生长抑素对Oddi括约肌功能的影响

本文在逆行胰胆管造影下,Oddi括约肌测压研究生长抑素对20例患者Oddi括约肌运动功能的影响。20例患者中胆总管结石6例,胆总管轻度扩张3例,肝门癌3例,未见明显异常者8例,用低顺应性水灌注系统,三通道测压导管,分别于用药前及静注生长抑素250#g 1分钟后进行Oddi括约肌测压,观察Oddi括约肌基础压、收缩频率、收缩幅度、收缩间期、传播方式和胆管内压变化。结果显示:用药后Oddi括约肌基础压降低,收缩频率减慢,其余指标无明显变化。我们认为,生长抑素对Oddi括约肌有抑制性作用,有利于胆汁和胰液排出。     

吲哚布芬对NA预收缩的大鼠离体胸主动脉环张力的影响

目的 研究吲哚布芬对去甲肾上腺素(NE)预收缩大鼠主动脉血管环的效应及其可能的机制.方法 记录NE预收缩的离体大鼠主动脉环张力变化,观察吲哚布芬对大鼠主动脉血管环的作用及不同工具药对吲哚布芬的影响.结果 吲哚布芬(1×10-7 mol/L~3×10-5 mol/L)对NE引起的大鼠主动脉血管环的张力变化有浓度依赖性的舒张作用.在NE预收缩的血管环上,四乙胺(10-2 mol/L)、4-氨基吡啶(10-3 mol/L)和格列苯脲(10-5 mol/L)可抑制吲哚布芬的舒张血管作用.结论 吲哚布芬对NA引起的血管收缩有浓度依赖行的舒张作用,吲哚布芬可能通过开放Kca通道、Kv通道和KATP通道参与了吲哚布芬的舒血管作用.     

Ethanol inhibits the motility of rabbit sphincter of Oddi in vitro

AIM: The role of the sphincter of Oddi (SO) in ethanol (ETOH)-induced pancreatitis is controversial. Our aim was to characterise the effect of ETOH on basal and stimulated SO motility.METHODS: SOs removed from white rabbits were placed in an organ bath (Krebs solution, pH7.4, 37℃). The effects of 2 mL/L, 4 mL/L, 6 mL/L and 8 mL/L of ETOH on the contractile responses of the sphincter were determined.1 SOs were stimulated with either 0.1μol/L carbachol, 1μol/L erythromycin or 0.1μol/L cholecystokinin (CCK).RESULTS: ETOH at a dose of 4 mL/L significantly decreased the baseline contractile amplitude from 11.98&#177;0.05 mN to 11.19&#177;0.07 mN. However, no significant changes in the contractile frequency were observed. ETOH (0.6%) significantly decreased both the baseline amplitude and the frequency compared to the control group (10.50&#177;0.01 mN,12.13&#177;0.10 mN and 3.53&#177;0.13 c/min, 5.5&#177;0.13 cycles(c)/min,respectively). Moreover, 0.8% of ETOH resulted in complete relaxation of the SO. Carbachol (0.1μol/L)or erythromycin (1μol/L) stimulated the baseline amplitudes (by 82% and 75%, respectively) and the contractile frequencies (by 150% and 106%, respectively). In the carbachol or en/thromydn-stimulated groups 2-6 mL/L of ETOH significantly inhibited both the amplitude and the frequency. Interestingly,a 4-5 min administration of 6 mL/L ETOH suddenly and completely relaxed the SO. CCK (0.1μol/L) stimulated the baseline amplitude from 12.37&#177;0.05 mN to 27.40&#177;1.82 mN within 1.60&#177;0.24 min. After this peak, the amplitudede creased to 17.17&#177;0.22 mN and remained constant during the experiment. The frequency peaked at 12.8&#177;0.2 c/min,after which the constant frequency was 9.43&#177;0.24 c/min throughout the rest of the experiment. ETOH at a dose of 4 mL/L significantly decreased the amplitude from 16.13&#177;0.23 mN to 14.93&#177;0.19 mN. However, no significant changes in the contractile frequency were observed. ETOH at a dose of 6 mL/L inhibited both the amplitudes and the frequencies in the CCK-stimulated group, while 8 mL/L of ETOH completely relaxed the SO.CONCLUSION: ETOH strongly inhibits the basal, carbachol,erythromycin, and CCK-stimulated rabbit SO motility.Therefore, it is possible that during alcohol-intake the relaxed SO opens the way for pancreatic fluid to flow out into the duodenum in rabbits. This relaxation of the SO may protect the pancreas against alcohol-induced damage.     

Interplay between nitric oxide and VIP in CCK-8-induced phasic contractile activity in the rabbit sphincter of Oddi

AIM: The sphincter of Oddi (SO) plays an important role in delivery of bile into the duodenum. To establish whether vasoactive intestinal polypeptide (VIP) and nitric oxide (NO) were involved in phasic contractile activity of the rabbit SO stimulated by cholecystokinin-octapeptide (CCK-8). METHODS: Isolated SO muscle rings were cleaned of fat and mounted horizontally on two small L-shaped hooks one of which was connected to a force transducer for the measurement of isometric tension.The experiments were carried out in a thermostatically controlled (37±0.2℃) organ bath (5 mL) containing Krebs solution.The organ fluid was gassed with 95% O2 and 50 mL/L CO2 to keep the pH at 7.40±0.05. Contractile responses to CCK-8 (1 μmol/L) were evaluated in the presence and absence of NG-nitro-L-arginine (LNNA), an inhibitor of NO synthase (100 μmol/L), and (p-chloro-D-Phe6-Leu17)-VIP (VlPa, 30 μmol/L), a VIP receptor antagonist. RESULTS: CCK-8 stimulated the phasic activity of the SO. NO synthase inhibition increased the frequency and amplitude of contractions with a slight increase in developed tension. Pre-incubation with VlPa also attenuated this CCK-8 effect. The combined application of LNNA and VlPa abolished the phasic activity of the muscle rings with a marked increase in tension in response to CCK-8. CONCLUSION: VIP and NO together contribute to an increase in phasic activity of SO.     

精氨酸对高胆固醇血症兔冠状动脉功能的效应

目的评价左-精氨酸对高胆固醇血症兔模型冠状动脉内皮舒张功能的效应。方法雄性日本大耳白兔36只随机分为3组:对照组、高胆固醇血症组、左-精氨酸组,每组12只。两周后,处死兔,取兔冠状动脉做成动脉环。结果与对照组比较,高胆固醇血症组、左-精氨酸组兔胆固醇水平明显增高;高胆固醇血症组兔冠状动脉环在KCl预收缩基础上对内皮依赖的(乙酰胆碱累积浓度10-8～10-4mol/L)效应减弱;左-精氨酸组兔对乙酰胆碱的舒血管反应明显减低,在高浓度(乙酰胆碱10-4mol/L)下表现为冠状动脉环的收缩(P<0.05)。结论左-精氨酸不能改善高胆固醇血症兔冠状动脉的内皮舒张功能。     

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.     

色满类化合物HEF-19对家兔离体肠管平滑肌的舒张作用

目的:探讨色满类化合物HEF-19对家兔离体小肠平滑肌的舒张作用及其机制.方法:采用家兔小肠离体实验法, 观察HEF-19对家兔离体小肠自发活动的影响, 研究BaCl2诱导收缩时格列苯脲(10-5 mol/L)、维拉帕米(10-7 mol/L )、酚妥拉明(10-7 mol/L)和普奈洛尔(10-7 mol/L)对HEF-19的舒张作用的影响.结果:HEF-19可以剂量依赖性地降低家兔离体小肠平滑肌自发性收缩的张力和振幅; 分别加入格列苯脲和维拉帕米孵育后,HEF-19(10-6 mol/L-10-3 mol/L)的舒张量效曲线均发生明显变化, EC50值分别由4.36±0.12mol/L和4.43±0.19 mol/L转变为4.16±0.22mol/L和3.96±0.24 mol/L, 差异具有统计学意义(P <0.05). 酚妥拉明和普奈洛尔对HEF-19的舒张作用没有影响.结论:HEF-19具有舒张小肠平滑肌的作用并且其作用机制与ATP-敏感性钾通道和L 型钙通道开放有关.而与α受体和β受体无关.     

NDP液对猪冠状动脉内皮长时间离体低温保存研究

目的探讨非去极化停跳液（non-depolarizing solution,NDP）对长时间低温（8h,4℃）保存猪冠状动脉内皮舒缩功能的影响。方法实验分为对照（Con）组、St.Thomas（ST）液组、Histidine-tryptophan-ketoglutarat（HTK）液组、非去极化停跳（NDP）液组。取冠状动脉的左前降支中下1/3段,截成长度为3mm的血管环,连接于血管张力模型上。平衡1h后,在相应的停跳液中、经4℃缺氧条件下保存8h,加入环加氧酶阻滞剂和一氧化氮合成酶阻断剂,记录由U46619及A23187引发的EDHF介导的血管收缩舒张反应。结果各种不同的停跳液4℃条件下保存8h后,ST组和HTK组血管环静息张力较对照组和NDP组显著上升。加入A23187后,HTK组和NDP组的最大舒张百分比分别为67.62%±19.06%和71.82%±12.22%,显著高于对照组（9.77%±5.28%）和ST组（14.46%±9.54%）。结论 NDP液对低温保存8h的冠脉血管内皮功能具有保护作用,其保护作用优于HTK液和St.Thomas液。     

法莫替丁及西咪替丁对Oddi括约肌压力变化的影响

目的:观察常规剂量的组胺H2受体阻滞剂法莫替丁、西咪替丁对Oddi括约肌(SO)运动功能的影响.方法:取胆道探查术后留有T型管患者20例,随机分为法莫替丁组和西咪替丁组(n=10),测量用药前后的十二指肠压(DP)、SO基础压(SOBP)、收缩幅度(SOCA)、收缩频率(SOF)、收缩间期(SOD)及胆总管压(CBDP).结果:静推西咪替丁10 min后,SOCA及SOBP分别下降了25.6%及57.3%,20 min后SOCA及SOBP分别下降了25.4%及19.3%,给药前后自身对照统计学上有显著差别(P＜0.05);静脉推注法莫替丁后SOCA及SOBP有降低趋势,但无统计学意义.其他指标无明显变化.结论:常规剂量的西咪替丁可引起SOBP和SOCA降低,对SO运动具抑制作用,常规剂量的法莫替丁对SO压力无明显影响.     

人参皂甙Rg1扩张兔基底动脉作用及其机制

目的 :观察人参皂甙 Rg1（G- Rg1）对基底动脉条的扩张作用 ,并探讨其作用机制。方法 :采用离体血管条灌流实验法 ,观察 G- Rg1对去甲肾上腺素 （NA ）、Ca Cl2 、KCl反应的影响 ,以及去除内皮细胞后 ,G- Rg1扩血管作用的变化。结果 :0 .1mm ol· L- 1及 0 .0 1mmol· L- 1 G- Rg1分别使 NA和 Ca Cl2 量效曲线明显右移 ,最大反应压低 ,非竞争性拮抗参数 p D2 ′分别为 3.6 4和 4.6 6。 G- Rg1对 NA依内 Ca2 +性收缩和依外 Ca2 +性收缩均具有显著的抑制作用。去除内皮可明显减弱 G- Rg1扩张 KCl诱导的收缩血管作用。结论 :G- Rg1既可通过抑制内 Ca2 +释放 ,也可抑制Ca2 +通过电压依赖性 Ca2 +通道的内流 ,舒张脑基底动脉 ,其舒张作用有内皮依赖性。     

Heart rate variability and circulating catecholamine concentrations during steady state exercise in healthy volunteers.

OBJECTIVES--To assess whether exercise induced suppression of heart rate variability in the low frequency domain (0.06-0.15 Hz) is related to the increase in circulating catecholamine concentrations. DESIGN--Randomised crossover trial of three exercise tests characterised by different workloads. Pharmacological simulation of exercise-induced changes in vagal and sympathetic activity. PARTICIPANTS--Six healthy men with a mean age of 31.2 (SD 3.0) years. INTERVENTIONS--Three different workloads of steady state cycling ergometry: control state without cycling, cycling at a target heart rate of 100 beats/min, and cycling at a target heart rate of 150 beats/min. Intravenous infusion of atropine (target heart rate 100 beats/min) followed by the additional infusion of adrenaline and noradrenaline. MAIN OUTCOME MEASURES--Fast Fourier analysis of heart rate variability; blood pressure; and venous plasma concentrations of lactate, adrenaline, and noradrenaline. RESULTS--During the control exercise period there were no changes in the assessed variables compared with the preceding resting period. During exercise at a heart rate of 100 beats/min systolic blood pressure increased and heart rate variability decreased. During exercise at a heart rate of 150 beats/min systolic blood pressure and lactate, adrenaline, and noradrenaline concentrations increased. In addition, low frequency (LF) was lower than during exercise at 100 beats/min, high frequency (HF 0.15-0.80 Hz) resembled that during exercise at 100 beats/min, and diastolic blood pressure was reduced. Infusion of atropine caused no changes in blood pressure or plasma concentrations of lactate, adrenaline, and noradrenaline and decreased heart rate variability. The additional infusion of adrenaline and noradrenaline completely suppressed heart rate variability and increased blood pressure. CONCLUSIONS--The reduction in LF and HF during exercise at a heart rate of 100 beats/min, which is not characterised by increased plasma catecholamine concentrations, and during atropine infusion suggests that heart rate variability in the supine state is largely influenced by vagal activity. The additional reduction in LF during exercise at 150 beats/min and during catecholamine infusion may reflect a negative feedback of circulating catecholamines on the sympathetic control of heart rate.     

Effect of areca on contraction of colonic muscle strips in rats

AIM: To investigate the effects of areca on the contractileactivity of isolated colonic muscle strips in rats andmechanism involved.METHODS: Each strip (LMPC, longitudinal muscle ofproximal colon; CMPC, circular muscle of proximal colon;LMDC, longitudinal muscle of distal colon; CMlC, circularmuscle of distal colon. ) was suspended in a tissue chambercontaining 5 mL Krebs solution (37 ℃), bubbledcontinuously with 950 mL@ L-1 O2 and 50 mL@ L-1 CO2 . Themean contractile amplitude (A), the resting tension (T),and the contractile frequency (F) were simultaneouslyrecorded on recorders.RESULTS: Arsca dose dependently increased the meancontractile amplitude, the resting tension of proximal anddistal colonic smooth muscle strips in rats ( P ＜ 0.05). Italso partly increased the contractile frequency of colonicsmooth muscle strips in rats ( P ＜ 0.05). The effects werepartly inhibited by atropine (the resting tension of LMPCdecreased from 0. 44 ± 0. 12 to 0. 17 ± 0.03; the restingtension 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 decreasedfrom 86.6± 17.3 to 32.8 ± 9.3; P＜ 0.05 vs areca), but theeffects were not inhibited by hexamethonium (P＞ 0.05).CONCLUSION: Areca stimulated the motility of isolatedcolonic smooth muscle strips in rats. The stimulation ofareca might be relevant with M reoeptor partly.