[Changes in the adrenergic mechanisms regulating cardiac activity and coronary circulation in experimental diabetes...

The effect of hyperglycemia on adrenergic response of the heart and coronary vessels was examined, using an alloxan diabetes model, in an experimental study involving catheterization, extracorporal perfusion and coronary arterial resistance measurement in dogs with intact thoracic cavities. Experimental diabetes mellitus was shown to be associated with enhanced positively chronotropic--and weakened negatively chrono- and inotropic--cardiac response to catecholamines introduced into the perfusion flow. Adrenergic reactive dilatation of coronary vessels was first enhanced, and later weakened, as glycemia progressed. It is assumed that a disturbance of hormonal interrelations due to insulin deficiency may play a role in the mechanism of changed adrenergic response of the heart and coronary vessels in experimental diabetes mellitus.