电刺激与高渗盐水注入室旁核对血压的影响及其机制的初步探讨

EFFECTS OF ELECTRIC AND HYPERTONIC SALINE STIMULATION OF PARAVENTRICULAR NUCLEUS ON BLOOD PRESSURE AND PRELIMINARY STUDY ON THE MECHANISM

本工作观察电刺激和微量高渗盐水注入室旁核(PVN)对蓝斑(LC)单位放电和血压的影响,以及阻断LC内精氨酸加压素(AVP)受体时PVN升压反应的变化,从而探讨PVN下行活动对LC单位放电的调制作用和LC在PVN调节血压过程中的地位。结果发现:(1)电刺激PVN使多数LC自发放电单位放电频率增高,并伴血压升高;(2)微量高渗盐水注入PVN也获得同样效果;(3)多数对电刺激PVN产生兴奋反应的LC单位,对高渗盐水注入PVN也表现为兴奋;(4)预先在LC注入AVP桔抗剂,可部分降低电刺激和高渗盐水注入PVN所引起的升压效应。上述结果提示:PVN调节血压的作用部分是通过PVN下行活动对LC功能影响实现的,PVN下行活动主要引起LC自发放电单位放电频率增加,并提示这一兴奋效应可能是由AVP介导的。

The present work was designed to investigate the effects of electric and hypertonic saline stimulation of paraventricular- nucleus (PVN) on unit discharge of locus coeruleus (LC) and blood pressure in rats. Both electric current (10 V, 100 Hz, 1 ms)and hypertonic saline (2% NaCl) stimulation of the PVN led to the increase in discharge frequency of the LC units and blood pressure. Microinjection of 1.0μg of AVP antagonist Cl-d(CH2)5 Tyr(Me) AVP] into the LC before stimulation reduced the pressor response induced by electric stimulation of PVN by 10.72±4.80% and that induced by hypertonic stimulation of PVN by 9.27 ± 6.83%. The results indicate that PVN stimulation elicits mainly excitation of LC and pressor response, and that the pressor response to PVN stimulation may be mediated, in part, via AVP receptors in the LC.