Role of nitric oxide in the inhibition of lipopolysaccharide-induced thoracic aortic hyporeactivity by cholecystokinin in vitro / 中国病理生理杂志

ABSTRACT

AIM: To investigate the effect of cholecystokinin octapeptide(CCK-8) on the L-arginine-nitric oxide(NO) pathway in rabbit thoracic aortae treated with lipopolysaccharide(LPS). METHODS: The isolated thoracic aortic rings(TARs) from rabbits were incubated with LPS, LPS+CCK or vehicle for 14 h. Then the contractility to phenylephrine(PE) by TARs and the response to L-arginine(L-Arg) by pre-contractile TARs were measured. In addition, we added NO synthase(NOS) inhibitors aminoguanidine(AG)and N ?-nitro-L-arginine(L-NNA) into organ baths to observe the changes of vascular contractility to PE. NOS activity in isolated TARs were also detected. RESULTS: Incubation of TARs with LPS for 14 h resulted in an increase of NOS activity and a reduction of contractility to PE. Treatment with CCK-8 significantly inhibited the increased NOS activity in thoracic aortae and improved the hypocontractility of TARs to the same degree as AG. CONCLUSION: CCK-8 may improve the hypocontractility of TARs induced by LPS by inhibiting the activity of NOS.