摘要
目的 研究外周α2 受体是否参与调制中枢外源性组胺 (HA)对颈动脉窦反射 (CBR)的重调定。方法 孤离麻醉SD大鼠的双侧颈动脉窦区 ,将不同窦内压 (ISP)与其对应的平均动脉压 (MAP)值进行Logistic五参数曲线拟合 ,根据所得ISP MAP关系曲线及其特征参数 ,观察脑室注射 (i.c .v.)HA以及预先外周静脉注射 (iv .)选择性α2 受体拮抗剂育亨宾 (YOH)对CBR的影响。结果 i.c .v.HA (6 0 μmol·L-1,5 μL)导致ISP MAP关系曲线明显上移 ,反射参数中阈压增大 (P <0 .0 5 ) ,MAP反射变动范围及反射最大增益减小 (P <0 .0 5 ) ;预先iv .YOH (2 .5 μmol·L-1,15 μL·10 0g-1体重 ) ,明显进一步加强HA的上述效应 ;单独iv .相同剂量的YOH对CBR无明显影响 (P >0 .0 5 )。结论 脑室给HA使CBR产生快速重调定 ,反射敏感性下降 ;外周α2受体作用可减弱i.c .v .HA对CBR的抑制性重调定。
Objective To determine the role of peripheral α 2 receptors in carotid sinus baroreflex (CBR) resetting induced by intracerebroventricular (i.c.v.) injection of histamine (HA).Methods The left and right carotid sinus regions were isolated from the systemic circulation in 31 male Sprague-Dawley rats 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 CBR performance induced by i.c.v. HA and the effects of pretreatment with α 2 receptor selective antagonist, yohimbine (YOH), into the peripheral vein on the responses of CBR to HA.Results I.c.v. HA (60μmol·L -1 in 5μL) significantly shifted the ISP-MAP relationship curve upwards and obviously decreased the value of the reflex parameters such as MAP changing range and maximum gain (P<0.05), but increased the threshold pressure (P<0.05). The peripheral pretreatment of YOH (2.5μmol·L -1, in 15 μL·100 g -1 weight) could obviously intensify the above-mentioned changes of CBR induced by HA. Only peripheral intravenous injection with the same dose of YOH did not change CBR performance significantly (P>0.05).Conclusion HA cerebroventricular administration could result in the rapid resetting of CBR, the decrease of reflex sensitivity and the responses of CBR to HA might be diminished by peripheral α 2 receptor activity.
出处
《中国血液流变学杂志》
CAS
2004年第3期312-314,共3页
Chinese Journal of Hemorheology
关键词
外周α2受体
脑室注射
组胺
颈动脉窦反射
平均动脉压
carotid sinus baroreflex
histamine
intracerebroventricular injection
peripheral α 2 receptors
mean arterial pressure
