应激性血压增高时交感紧张性与动脉压力感受反射的变化

ALTERATIONS IN SYMPATHETIC TONE AND BAROREFLEX SENSITIVITY DURING THE GENESIS OF HYPERTENSION

１４６只雄性Ｗｉｓｔａｒ大鼠，慢性应激２０天，诱发早期可逆性应激性高血压，在应激４～１６天血压逐渐增高的高血压发生期，同时观察交感紧张性和动脉压力感受反射敏感性的变化。结果发现，交感紧张性升高超前于血压的变化，随后在血压继续升高过程中趋于回降，动脉压力感受反射则伴随血压升高而逐渐衰减。这提示，交感紧张性升高主要在高血压发生中起重要作用，动脉压力感受反射的衰减，可能参与高血压的发展和维持，两者的产生可能来源于不同的中枢机制。

One hundred forth six Wister male rats were stressed chronically by footshock for 20 days to induce early reversible stress-induced hypertension. During the genesis of hypertension, from the 4th through 16th day in stress, changes in heart rate (HR) and urinary catecholamine were studied to investigate the sympathetic tone response, and the sensitivity of baroreflex was observed simultaneously. The results showed that: ① During stress for 4-8 days the sympathetic tone elevated before the increase of BP and thereafter it showed a tendency to recover while BP increased continuously. ② The sensitivity of baroreflex attenuated gradually following the increase of BP. The HR response of baroreflex attenuated eaclier than the renal sympathetic nerve activity (RSNA) response and the afferent function of baroreflex revealed no significant change in hypertensive rats, both of which suggest that the functional change in baroreflex centre is mainly responsible for this attenuation. It is concluded that the increase in sympathetic tone may play an important role in the genesis of hypertension and the attenuation of baroreflex may participate in the development and maintenance of hypertension, and probably thay have different central mechan isms.