电针大鼠“足三里”穴对防御性升压反应的抑制作用及其机制分析

wistar大鼠,用乌拉坦和氯醛醣腹腔麻醉。电刺激下丘脑“防御反应区”诱发升压反应。用低频低强度电针“足三里”、“内关”、“华佗夹脊”穴,可抑制下丘脑性升压反应(HPR),而高频高强度刺激上述三个穴位或低频低强度电针“悬钟”穴则无效。电针“足三里”穴对HPR的抑制作用在切断双侧颈迷走神经后仍出现,提示此作用是通过抑制心血管交感中枢而实现。微量注射5-羟色胺(5-HT)8μg/10μl于第四脑室内,则可降低基础血压和HPR,若注射5-HT的受体拮抗剂肉桂硫胺8μg/10μl于第四脑室,可阻断电针对HPR的抑制效应。以上结果表明,电针“足三里”穴可抑制HPR,脑内5-HT系统可能在电针对HPR的抑制效应中起重要作用。

INHIBITORY EFFECT OF ELECTROACUPUNCTURE OF"ZUSANLI" POINT ON PRESSOR RESPONSE INDUCED BY HYPOTHALAMIC STIMULATION IN THE RAT

Experiments were performed on 36 Wistar rats anesthetized with urethane and chloralose. Pressor response was induced by electrical stimulation of the hypothalamic defence area. Low frequency and low intensity electroacupuncture of "Zusanli"and "Neiguan" and "Hua Tuo Jia Ji"point oould significantly reduce the pressor response induced by stimulation of the hypothalamio defence area. However, no significant hypothalamio pressor response (HPR) was observed by stimulation with high frequeaoy and high intensity or by low frequency and low intensity eleotroaoupunoture stimulation of "Xuanzhong" point. The inhibitory HPR effect of electroacupunoture applied to "Zusanli" point might be caused by inhibition of the cardiac sympathetic center, as these effects still persisted after bilateral vagotomy. Mioroinjeotion of 5-HT into the 4th-ventricle decreased the basic blood pressure and HPR. When 5-HT receptor antagonist cinanserine waa given into the 4th vantriole, eleotroaoupunoture of "Zusanli"no longer reduced, HPR. These results suggest that activation of the 5-HT receptor in the hindbrain may be responsible for decrease in basic blood pressure and inhibition of HPR, and is necessary for the inhibitory effect of "Zusanli" eleotroaoupunoture on HPR.