The effect of 4-week streptozotocin-induced diabetes on responses to endothelin-1 in rat isolated atria.
The effect of endothelin-1 has been examined on isolated spontaneously beating right atria and electrically driven left atria from diabetic rats and age-matched controls. Diabetes was induced by a single i.v. injection of streptozotocin (65 mg/kg) 4-5 weeks before the experiments. Endothelin-1 (0.01-100 nM) caused concentration-dependent increases in atrial rate and force; the increases were not different between atria from diabetic and control rats. The ability of endothelin-1 to reduce chronotropic and inotropic responses to noradrenaline was also not different between the two groups. Endothelin-1 (10 nM) decreased the chronotropic response to sympathetic nerve stimulation (2 Hz, 10 s) in atria from control rats by 68 +/- 5% (n = 8), but this decrease was slightly smaller (45 +/- 6%, n = 8) in atria from diabetic rats. The results provide no evidence to suggest that the diabetic state markedly alters cardiac responses to endothelin-1.
Reid
J J
JJ
Department of Pharmacology, University of Melbourne, Melbourne, Victoria 3052, Australia.
Lieu
A T
AT