Abstract
Aims/hypothesis. To investigate cardiac repolarization time in streptozotocin-induced diabetic rats and isolated hearts perfused with high glucose concentration. Methods. We studied the effects of streptozotocin-induced diabetes on the cardiac repolarisation time (Q-T interval) in Sprague-Dawley rats during a 4-day period of hyperglycaemia and a subsequent 4-day period of normoglycaemia. The Q-T interval was also evaluated in isolated hearts of non-diabetic rats, in condition of high glucose concentration. Results. Hyperglycaemia in streptozotocin rats increased mean blood pressure and led to a significant (p < 0.001) prolongation of Q-T values, which normalized after 4 days of normoglycaemia with intravenous insulin infusion. Perfusion of isolated hearts in condition of high glucose concentration caused a significant prolongation of Q-T values and increased coronary perfusion pressure (p < 0.001). The effects of high glucose were completely prevented by glutathione and almost completely by l-arginine, the natural precursor of nitric oxide. In a condition of normal glucose, l-NAME, an inhibitor of endogenous nitric oxide synthesis, increased both Q-T and CPP values to levels similar to those induced by high glucose (p < 0.001). Verapamil completely prevented Q-T lengthening and reduced by about two-thirds CPP values (p < 0.001). Conclusion/Interpretation. Streptozotocin-diabetes in rats produces significant haemodynamic and electric perturbations that are reversed by normoglycaemia. Moreover, high glucose increases Q-T and CPP values in the isolated hearts of non-diabetic rats. The latter effects are reversed by glutathione and l-arginine, partially reversed by verapamil and mimicked by l-NAME. By increasing the production of free radicals, high glucose could reduce nitric oxide availability to target cells inducing a state of increased vasomotor tone and ventricular instability. [Diabetologia (2001) 44: 464–470]
Article PDF
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 12 September 2000 and in revised form: 2 November 2000
Rights and permissions
About this article
Cite this article
D'Amico, M., Marfella, R., Nappo, F. et al. High glucose induces ventricular instability and increases vasomotor tone in rats. Diabetologia 44, 464–470 (2001). https://doi.org/10.1007/s001250051644
Issue Date:
DOI: https://doi.org/10.1007/s001250051644