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Effects of cholecystokinin octapeptide on rat cardiac function and the receptor mechanism

Zhao Xiaoyun, Ling Yiling, Meng Aihong, Shan Baoen, Zhang Junlan

Department of Pathophysiology,Hebei Medical University.Shijiazhuang 050017,Hebei；China

Abstract

The aim of this study was to explore the effects of cholecystokinin octapeptide (CCK-8) on cardiac function an the receptor mechanism in anesthetized rats. The mean arterial pressure (MAP), heart rate (HR), the left ventricle systolic pressure (LVP) and the maximal/minimum rate of LVP (±LV dp/dt_(max)) were measured. The results obtained are as follows. (1) Low dose of CCK-8 (0.4#mu#g/kg i.v.) caused tachycardia and slight increase in MAP, LVP and ±LV dp/dt_(max) (P<0.01), while medium dose (4.0 #mu#g/kg i.v.) and high dose of CCK-8 (40#mu#g/kg i.v.) elicited a bradycardia and marked increase in MAP, LVP and ±LV dp/dt_(max) (P<0.01). (2) Proglumide (1.0mg/kg i.v.), a CCK-receptor (CCK-R) antagonist, significantly inhibited the pressor effects of CCK-8, whilst it reversed the bradycardic responses (P<0.01). (3) Using reverse transcription polymerase chain reaction (RT-PCR), CCK-A receptor (CCK-AR) and CCK-B receptor (CCK-BR) mRNA were expressed in myocardium of rats. The above results indicate that CCK-8 may enhance cardiac function in a dose-dependent manner and elicit a change in HR, which is likely induced by the activation of CCK-R on myocardium.

Key words: Cholecystokinin;Cardiac function;Receptor

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Citing This Article：

Zhao Xiaoyun, Ling Yiling, Meng Aihong, Shan Baoen, Zhang Junlan. Effects of cholecystokinin octapeptide on rat cardiac function and the receptor mechanism. Acta Physiol Sin 2002; 54 (3): (in Chinese with English abstract).