Effect of streptozotoxin-induced diabetes on cAMP-mediated dilation in rat small coronary arteries
- VernacularTitle:链脲佐菌素诱发的大鼠糖尿病对cAMP介导的小冠状动脉舒张的影响
- Author:
Qiang CHAI
- Publication Type:Journal Article
- Keywords:
Diabetes mellitus;
Coronary artery;
Cyclic AMP;
Potassium channels;
GTP-binding regulatory protein
- From:
Chinese Journal of Pathophysiology
1989;0(06):-
- CountryChina
- Language:Chinese
-
Abstract:
AIM: To study the effect of streptozotoxin-induced diabetes on cAMP-mediated dilation of rat small coronary arteries (RSCA). METHODS: The diabetes models were induced by injection of streptozotoxin (STZ) to tail vein. The dilation of RSCA was examined by videomicroscopy measurement. RESULTS: (1) STZ diabetes reduced dilation induced by isoproterenol (ISO), operating through cAMP mechanism, in RSCA. This response was in a dose-dependent manner and endothelium-independent relation. (2) STZ diabetes reduced response of RSCA to adenylyl cyclase agonist forskolin and to adenylyl cyclase inhibitor SQ 22536. (3) The 4-aminopyridine, a Kv channel blocker of vascular smooth muscle, suppressed the dilation induced by ISO and forskolin in RSCA of STZ diabetes. (4) The NaF, a G-protein stimulator, reduced the response in RSCA of STZ diabetes. CONCLUSIONS: Although it is known that diabetes impairs endothelium-dependent vasodilation, the effect of diabetes on dilation mechanism independent of endothelium is not well understood. In the present study, it is demonstrated that dilation is reduced in STZ rat small coronary arteries via cAMP signal mechanism and Kv channel of vascular smooth muscle. The G-protein is able to influence this dilation mechanism.
