Vascular responses to norepinephrine and bethanechol in isolated aortae from 2-month diabetic rabbits induced by alloxan.

The present study examined responses to norepinephrine and bethanechol in isolated aortae from 2-month diabetic rabbits induced by alloxan. Alloxan (100 mg/kg) was administered intravenously into the ear vein, and the blood glucose levels were estimated weekly for a duration of 2 months. The aortae from 2-month diabetic rabbits were removed and the aortic responses to norepinephrine and bethanechol were tested in vitro. The data showed that the aortic response to norepinephrine was increased but the aortic response to bethanechol was decreased in diabetic aortae; however, changes of responses were insignificant in comparing with those of the age-matched control aortae. It was speculated that a longer duration of diabetic development should be helpful to ensure a significant change of aortic response to vasoactive agents.