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激动中枢组胺能受体对应激大鼠颈动脉窦压力感受性反射重调定的影响

王国卿, 周希平, 黄伟秋

苏州大学医学院基础医学系生理学教研室，苏州215007

摘要

应激1周的大鼠，麻醉后孤离双侧颈动脉窦区，将不同窦内压(ISP)与其对应的平均动脉压(MAP)值进行Logistics个参数曲线拟合。根据所得ISP- MAP关系曲线及其特征参数，分别观察侧脑室((i. c. v.)注射和孤束核(NTS)内注射组胺受体拮抗剂对颈动脉窦压力感受性反射(CS R)的影响，并与相应的非应激CSR水平进行比较。结果如下:(1)应激导致ISP- MAP关系曲线显著全面上移，窦内压和增益(ISP- Gain)关系曲线中部明显下移，反射参
数中闭压(TP)、饱和压(SP)、调定点(set point)和最大增益时的窦内压(I S P Gmaa)值增大，MAP反射变动范围(MAPrange)及反射最大增益(Gmaa)减小;(2) I. c. v. H,或Hz受体拮抗剂氯苯p比胺(CHL) 5 ug或西咪替丁(CI M) 1 5 jig,在20 min内均可明显减弱应激对CSR的上述改变，CI M的这种减弱作用不如CHL的显著;(3) NTS内注射CHL(0. 5 jig)或CI M (1-5 jig)，对应激所致CSR变化的影响与i. c. v. CHL或CI M后的相类似;(4)分别i. c. v.和NTS内注射CHL或CI M后，均不能使应激的CSR水平完全恢复到相应的非应激对照水平。以上结果提示，应激引起CSR重调定，反射敏感性下降;其部分机制可能是激活中枢组胺能系统，通过中枢组胺能受体(H,和Hz受体)尤其是H,受体介导而发挥作用;下丘脑一NTS的组胺能通路可能是应激导致CSR重调定的下行通路之一。

关键词： 颈动脉窦压力感受性反射; 应激; 氯苯砒胺; 西咪替丁; 侧脑室注射; 孤束核; 平均动脉压

Effects of central histaminergic receptor activation on carotid sints baroreceptor reflex resetting in stressed rats

WANG Guo- Qing, ZHOU Xi-Ping, H UANG Wei- Qiu

Department of Physiology，Medical School，Soochow University，Suzhou 215007

Abstract

To determine the effect of stress on carotid sinus baroreceptor reflex(CS助and whether or not central histaminergic receptors modulate the CSR under stress，the characteristics of CSR were analyzed by using an isolated carotid sinus preparation in Wistar rats .Animals were divided into two groups
at random:unstressed group(n一42) and stressed group(n一41).According to the site of microinjec tion of histaminergic receptor antagonists，each group was subdivided into a group of intracerebroventricular injection(i. c. v.)and a group of microinjection into the nucleus of the solitary tract(NTS).The volume of injection into the lateral cerebroventricle and NTS was 5 p1 and 1 p1，respective1y.Stressed groups were su匀ected to unavoidable electric foot-shock twice daily for a week，each session of foot shock lasted 2 hours .The left and right carotid sinus regions were isolated from the systemic cir
culation under anesthesia with pentobarbital sodium in all rats .The intracarotid sinus pressure(ISP) was altered in a stepwise manner to trigger CS R from 0 to 280 m m Hg at every step of 40 m m Hg and 4 s，and
then returned to 0 m m Hg in similar steps.ISP and mean arterial pressure(MAP) were recorded simultaneously .ISP- MAP relationship curve was constructed by fitting to the logistic function with five parameters .The CSR parameters and the ISP- MAP relationship curve were separately compared statistically.
The main results obtained are as follows.(1) Stress significantly shifted the ISP- MAP relationship curve upwards and obviously moved the middle part of ISP- Gain relationship curve downwards，and decreased the value of the MAP range and maximum gain(Gmax)，but increased the threshold pressure(T P)，sat-
uration pressure(S P)，set point and ISP at Gmax( ISPcmax).(2) I. c. v. of H, receptor antagonist chlorpheniramine(CHL，5 pg) or HZ receptor antagonist cimetidine(CI M，1 5 pg) significantly diminished the above mentioned changes in CSR performance induced by stress;the alleviative effect of CI M was
less re markable than that of CHL .The responses of CS R in stressed rats to H, or HZ receptor antagonists generally occurred 20 min after the administration and lasted approximately for 15 min.(3)After microinjection of CHL(0. 5 pg) or CI M(1 .5 pg) into the NTS，the responses of CSR in stressed groups were similar to those after i. c. v. injection of CHL or CI M.(4) However，microinjection of CHL or CI M into the lateral cerebroventricle or the NTS could not completely abolish the stress-induced changes
in CSR .These findings suggest that stress results in a resetting of CSR，a decrease in reflex sensitivity.The stress-induced changes in CSR may be mediated，at least in part，by activating the brain histamines
gic syste m .The central histaminergic receptors(H, and HZ receptors) may play an important role in the resetting of CSR under stress .The descending histaminergic pathway from the hypothalamus to NTS may be involved in these effects.

Key words: Carotid sinus baroreceptor reflex;Stress;;;;;

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引用本文：

王国卿, 周希平, 黄伟秋. 激动中枢组胺能受体对应激大鼠颈动脉窦压力感受性反射重调定的影响[J]. 生理学报 2003; 55 (1): .

WANG Guo- Qing, ZHOU Xi-Ping, H UANG Wei- Qiu. Effects of central histaminergic receptor activation on carotid sints baroreceptor reflex resetting in stressed rats. Acta Physiol Sin 2003; 55 (1): (in Chinese with English abstract).