Inhibitory effect of cholecystokinin octapeptide on carotid sinus nerve afferent discharge in anesthetized rats
- VernacularTitle:八肽胆囊收缩素对大鼠颈动脉窦神经传入放电的抑制作用
- Author:
Yixian LIU
;
Hao ZHANG
;
Jinghui DONG
;
Qian LI
;
Ruirong HE
- Publication Type:Journal Article
- Keywords:
cholecystokinin octapeptide;
carotid sinus;
pressoreceptors;
proglumide;
Bay K8644;
NG-nitro-L-arginine methylester
- From:
Chinese Journal of Pharmacology and Toxicology
2005;19(1):18-23
- CountryChina
- Language:Chinese
-
Abstract:
AIM To study if cholecystokinin octapeptide (CCK-8) alter cardiovascular functions by its direct inhibitory effect on carotid sinus baroreceptor (CSB) activity. METHODS The functional curve of carotid baroreceptor (FCCB) was constructed and the functional parameters of carotid baroreceptor were measured by recording sinus nerve afferent discharge in anesthetized male rats with perfused isolated carotid sinus. RESULTS ① CCK-8 0.1, 0.5 and 1.0 μmol·L-1 shifted FCCB to the right and downward, with a marked decrease in peak slope and peak integral value of carotid sinus nerve discharge in a concentration-dependent manner, indicating the inhibitory effect of CCK-8 on CSB activity. ② Pretreatment with proglumide (100 μmol·L-1), a nonselective CCK receptor antagonist, or Bay K8644 (0.5 μmol·L-1), an agonist of calcium channel, partially attenuated the inhibitory effect of CCK-8 (0.5 μmol·L-1) on CSB activity. Pretreatment with L-NAME (100 μmol·L-1), an inhibitor of NO synthase, did not affect the inhibitory action of CCK-8. CONCLUSION CCK-8 inhibits CSB activity, which may be mediated by activating CCK receptors in the carotid sinus area and thereby resulting in an inhibition of stretch-sensitive channels and decrease in Ca2+ influx.
