The role of feed back system from peripferal arterial pressure senser to hypothalamus in the development of hypertension

本研究旨在探讨下丘脑-交感神经系统与血管和肾脏压力敏感系统之间的反馈关系。(1)肾脏和下丘脑。正常血压大鼠对下丘脑后部刺激的升压和增加的交感神经反应可被去肾神经减弱。去肾神经可减轻DOCA/盐处理的大鼠和SHR的高血压发展，并抑制下丘脑的过度活动。提示肾通过肾神经调节下丘脑的敏感性，在高血压的发生发展中起一定作用。(2)压力感受性反射和下丘脑。去窦弓神经(SAD)不能改变DOCA/盐性高血压大鼠的高血压发展。在DOCA/盐处理的大鼠中，SAD不能改变下丘脑的感觉过敏。在DOCA/SALT高血压大鼠的高压期和高血压前期，对主动脉降压神经(ADN)刺激的心血管和交感神经抑制反应减弱，而对下丘脑的刺激反应增强。这些发现提示，压力感受器反射在高血压形成之前可能已经减弱，并参与了高血压和下丘脑多动的发生。(3)心肺反射和下丘脑。切断迷走神经不改变心血管和交感神经对下丘脑刺激的反应，迷走神经切断包括心肺感受器的传入纤维。综合上述结果，下丘脑接受来自肾脏和压力感受器的重要信息，以调节心血管系统。在高血压中，这种反馈系统可能会改变，并有助于高血压的发展。

This study was planned to determine the feed back relationship between the hypothalamo -sympathetic nerve sytem and pressure sensitive systems of vessels and kidneys.(1)Kidney and Hypothalamus. Pressor and incresed sympathetic nerve responses to posterior hypothalamic stimulations were attenuated by renal denervations in normotensive rats. Renal denervation attenuated the development of hypertension in DOCA/salt treated rats and SHR, with the inhibition of hypothalamic hyperactivity. These findings suggest that kidney regulate hypothalamic sensitivity via renal nerves and play some role in the development of hypertension.(2)Baroreflex and Hypothalamus. Sinoaortic denervation (SAD) could not alter the development of hypertenion in DOCA/salt hypertensive rats. Hypothalamic hypersentivity did not modified by SAD in DOCA/salt treated rats. Cardiovascular and sympatho-inhibitory responses to aortic depressr nerve (ADN) stimulations were attenuated in the hypertesnive and pre-hypertensive stage of DOCA/salt hypertensive rats, while responses to hypothalamic stimulations were augmented. These findings suggest that baroreflex may be attenuated before the development of hypertension and contribute to the development of hypertension and hypothalamic hyperactivity.(3)Cardiopulmonary reflex and Hypothalamus. Cardiovascular and sympathetic nerve responses to hypothalamic stimulations were not changed by vagus cut which includes the afferent fibers from cardiopulmonary receptors.Taken together all findings, hypothalamus receives the importnat informations from the kidney and baroreceptors to regulate cardiovascular system. In hypertension, this feed back system may be altered and contribute to the development of hypertension.