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Cholecystokinin octapeptide inhibits carotid sinus baroreflex in anesthetized rats

Liu Yixian, Zhang Hao, Ma Huijie, He Ruirong

Department of Physiology,Institute of Basic Medicine,Hebei Medical University.Shijiazhuang 050017,Hebei

Abstract

The results obtained are as follows: (1) By perfusion with CCK-8 (0.1, 0.5, 1.0 #mu#mol/L), the functional curve of baroreflex was shifted to the right and upward, with a decrease in peak slope (PS) (P<0.001) and a reflex decreased (RD) in mean arterial pressure, while the threshold pressure (TP) and saturation pressure (SP) were significantly increased. Among the functional parameters of carotid sinus baroreflex, the changes in RD, PS and TP were dose-dependent. (2) Pretreatment with proglumide (100 #mu#mol/L), a nonselective CCK receptor antagonist, the inhibitory effect of CCK-8 (0.5 #mu#mol/L) on the baroreflex was significantly attenuated. (3) Pretreatment with L-NAME (100 #mu#mol/L), an inhibitor of nitric oxide (NO) synthase, did not affect the inhibitory action of CCK-8 (0.5 #mu#mol/L). (4) Preperfusion with Bay K 8644 (500 nmol/L), an agonist of calcium channel, could attenuate the effect of CCK-8 (0.5 #mu#mol/L). It is suggested that the inhibitory action of CCK-8 on the baroreflex may be mediated by the activation of its receptors in the carotid sinus baroeceptor, leading to an inhibition of stretch-sensitive channels and a decrease in Ca~(2+) influx. However, NO released from the endothelium seems not to be involved in the mechanism of this effect.

Key words: 八肽胆囊收缩素;丙谷胺;Bay K 8644;压力感受器反射;L-NAME;平均动脉压

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Citing This Article：

Liu Yixian, Zhang Hao, Ma Huijie, He Ruirong. Cholecystokinin octapeptide inhibits carotid sinus baroreflex in anesthetized rats. Acta Physiol Sin 2004; 56 (1): (in Chinese with English abstract).