A significant increase of aortic response to a combination of norepinephrine and KCl in aorta isolated from 2-month diabetic rats induced by streptozocin.

A significant increase of diabetic aortic response to a single vasoactive agent usually occurs after 3 months of streptozocin-induced diabetes. The present study was to evaluate if a significant increase of aortic response to a combination of norepinephrine and KCl in vitro in 1- and 2-month diabetic rats. The results showed that the aortic response to a combination of norepinephrine and KCl was significantly increased in 2-month diabetic aorta than in age matched control aorta, even though the aortic contraction induced by norepinephrine or KCl alone is insignificant. These data suggest that the earliest time to demonstrate a functional change in vascular reactivity after the streptozocin administration is more than one month of diabetic development.