摘要
目的探讨蓝斑H_2受体是否影响应激对颈动脉窦反射(CSR)的重调定。方法应激1周的SD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Logistic曲线拟合,求得ISP-MAP关系曲线及其特征参数,观察蓝斑注射选择性H_2受体拮抗剂西咪替丁(CIM)对CSR的影响。结果蓝斑内注射CIM(1．5μg/μ1)导致应激大鼠ISP-MAP关系曲线后半程明显下移(P＜0．05),反射参数中阈压、饱和压和最大增益时的窦内压值均减少(P＜0．05)；蓝斑注射相同剂量的CIM对非应激大鼠的CSR无明显影响(P＞0．05)蓝斑内注射CIM不能使应激的CSR水平恢复到非应激给药后水平。结论蓝斑H_2受体参与应激对CSR的重调定；除此之外,应激作用中尚有其他因素的参与。
Objective To investigate the effects of H2 receptors in the locus ceruleus （LC） on carotid sinus reflex （CSR） resetting resulted from the stress. Methods Male Sprague-Dawley rats were randomly divided into two groups： unstressed （n=8） and stressed group （n=9）. The latter was subjected 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 circulation in all animals anesthetized with pentobarbital sodium. The intracarotid sinus pressure （ISP） was altered in a stepwise manner in vivo. ISP-mean arterial pressure （MAP） relationship curve and its characteristic parameters were constructed by fitting to the logistic function with five parameters. We observed the changes in CSR performance induced by stress and the effects ofmicroinjection with H2 receptor selective antagonist, cimetidine （CIM）, into the LC on the responses of CSR to stress. Results Microinjection of CIM （1.5 μg, in 1 μ1） significantly shifted posterior half range of ISP-MAP relationship curve downwards （P〈0.05） and obviously decreased the value of the reflex parameters such as threshold pressure, saturation pressure and ISP at maximum gain （P〈0.05） in the stressed rats. Microinjection with the same dose of CIM into the LC in the unstressed rats did not change CSR performance significantly （P〉0.05）. The changes in the stressed CSR performance resulted from the microinjection of CIM into the LC did not recover the levels of unstressed CSR after injection. Conclusion H2 receptors in the LC is involved in the stress-induced CSR resetting, and at the same time, the effects of stress on CSR also have other mechanism.
出处
《实验动物与比较医学》
CAS
2006年第4期235-238,共4页
Laboratory Animal and Comparative Medicine
基金
苏州大学医学院科学技术项目(编号:1995A-1)
关键词
颈动脉窦反射重调定
应激
蓝斑H2受体
平均动脉压
大鼠
Carotid sinus reflex resetting
Stress
H2 receptors in the locus ceruleus
Mean arterial pressure
Rat
