室旁核在刺激中脑防御反应区诱发防御性升压反应中的作用

雄性ＳＤ大鼠,用乌拉坦（７００ｍｇ／ｋｇ）和氯醛糖（３０ｍｇ／ｋｇ）腹腔麻醉。实验结果：（１）每隔５ｍｉｎ电刺激中脑导水管周围灰质背侧部“防御反应区”（ｄＰＡＧ）,持续观察５０ｍｉｎ,可见恒定的升压反应。若电解毁单侧室旁核（ＰＶＮ）区。１ｈ后,电刺激中脑ｄＰＡＧ区诱发的升压反应幅度部分减小。而损毁穹隆部、下丘脑前部、下丘脑背内侧核、下丘脑腹内侧核则无上述效应。（２）电刺激或微量注射高半胱胺酸（ＤＬ

Role of paraventricular nucleus in pressor response induced by dorsol part of midbrain periaqeductal gray stimulation

Experiments were carried out on male SD rats anesthetized with urethane (700 mg/kg) and chloralose (35 mg/kg). The results were as follows: (1) The pressor response could be elicited by electrical stimulation of dorsol part of midbrain periaqueductal gray (dPAG) for 5 s every 5 min. The pressor response for each series of dPAG stimulation within 50 min was constant. This pressor response could be decreased by electrolytic cauterization of paraventricular (PVN) area, but unaffected by electrolytic lesion of fornix, anterior hypothalamic area, nucleus dorsomedialis hypothalami and nucleus ventromedicalis hypothalami. (2) Microinjection of an AVP-V1 receptor antagonist (CH2)5 Tyr(Me)2AVP] (each side 0.1 nmol/0.1 microliter) into the bilateral rostral ventrolateral medulla (rVLM) partially inhibited the pressor response induced by PVN stimulation or by microinjection of D,L-homocysteric acid (DLH) (0.1 mol/0.2 microliter) into the PVN, but the mean artrtial pressure (MBP) and heart rate (HR) did not show any change when an AVP-V1 receptor antagonist or DLH was only used. (3) Microinjection of an AVP-V1 receptor antagonist into the bilateral rVLM partially inhibited the pressor response induced by dPAG stimulation. Therefore it is suggested that the effect of vasopression (AVP) released from PVN on the pressor response induced by dPAG stimulation is partly mediated by activation of AVP-V1 receptor in the rVLM.