Sandor P, Petty M, de Jong W, Palkovits M, de Wied D
Marion Merrell Dow Research Institute, Strasbourg, France.
Brain Res. 1991 Dec 6;566(1-2):212-8. doi: 10.1016/0006-8993(91)91701-2.
Experiments were carried out in urethane anaesthetized, ventilated rats to determine if brain arginine-vasopressin (AVP) plays a physiological role in cerebral blood flow autoregulation. Autoregulation was tested by determining local hypothalamic blood flow in the mediobasal hypothalamic area (HBF; H2-gas clearance technique) during consecutive stepwise lowering of systemic mean arterial pressure to 80, 60 and 40 mm Hg, by hemorrhage. Endogenous AVP was blocked by transecting the rostral, lateral and dorsal neuronal connections of the hypothalamus (including the median eminence) from all major brain areas, by bilateral transection of the vasopressin-containing fibres in the hypothalamo-hypophyseal tract to the median eminence at the level of the lateral retrochiasmatic area (RCAL), and finally by intracerebroventricular (i.c.v.) administration of an AVP antagonist, d(CH2)5Tyr(Me)AVP (AAVP). Significant increases of daily water intake indicated impaired vasopressin release following both types of surgical transection. Resting HBF was significantly elevated both after surgical isolation of the hypothalamus and after 10 ng AAVP administration compared to controls. Blood flow autoregulation in the hypothalamic region was seriously impaired following surgical isolation of the hypothalamus. However, HBF autoregulation remained just as effective as that of the control rats following either selective bilateral transection of the vasopressin pathways or following AAVP treatment. The present data indicate that AVP may play a role in the control of resting hypothalamic blood flow, but does not support a role of AVP in HBF autoregulatory mechanisms.
实验在经氨基甲酸乙酯麻醉、通气的大鼠身上进行，以确定脑内精氨酸加压素（AVP）在脑血流自动调节中是否发挥生理作用。通过在系统性平均动脉压连续逐步降至80、60和40毫米汞柱（通过放血实现）过程中，测定内侧基底下丘脑区域的局部下丘脑血流（HBF；氢气清除技术）来测试自动调节功能。通过切断下丘脑从所有主要脑区的 Rostral、外侧和背侧神经元连接（包括正中隆起）、在外侧视交叉后区域（RCAL）水平双侧切断下丘脑 - 垂体束中含加压素的纤维至正中隆起，以及最后通过脑室内（i.c.v.）给予AVP拮抗剂d(CH2)5Tyr(Me)AVP（AAVP）来阻断内源性AVP。每日饮水量的显著增加表明两种手术切断后加压素释放受损。与对照组相比，下丘脑手术分离后和给予10纳克AAVP后静息HBF均显著升高。下丘脑手术分离后，下丘脑区域的血流自动调节严重受损。然而，在加压素途径选择性双侧切断或AAVP治疗后，HBF自动调节与对照大鼠一样有效。目前的数据表明，AVP可能在静息下丘脑血流控制中发挥作用，但不支持AVP在HBF自动调节机制中的作用。
