Lack of significant alteration of histamine-induced response in aorta from diabetic rats induced by streptozocin.

Effect of histamine on aortic contraction between age-matched control and diabetic rats induced by streptozocin were compared in vitro. It was shown that the aortic response to histamine in 12-week diabetic rats remained unchanged, even though the methoxamine-induced contraction was potentiated significantly in diabetic aorta. The significant potentiation of the methoxamine-induced aortic contraction implies that the diabetes-induced change in aortic response to drugs has occurred in 12-week diabetic aorta. Since histamine is an endothelium dependent vasoactive agent, the lack of change of the histamine-induced response in 12-week diabetic aorta suggests that the histamine receptors in the endothelium are unlikely modified after 12 weeks of diabetic development.