Enhanced apomorphine-induced hypothermia in alloxan-treated rats.

Previous studies have indicated that drug-induced experimental diabetes is associated with increased receptor binding in the rat brain. The purpose of this study was to determine whether the dopamine receptor agonist apomorphine (APO) might produce an accentuated hypothermic response in rats rendered diabetic by alloxan (ALX) treatment. In a previous study, however, the only controls used were ALX-treated rats that failed to develop glycosuria. Therefore, in this study, APO (0.5 mg/kg IP) was administered to ALX-diabetic and non-diabetic as well as saline-treated control rats to ascertain whether the APO responsiveness of ALX-non-diabetic rats was comparable to that of saline control animals. ALX-diabetic rats experienced significantly greater hypothermic response to APO than did the saline control animals. Although ALX-non-diabetic rats were similar to the saline control animals in body weight and blood glucose levels, they too were hyperresponsive to APO. These findings indicate that pancreatic injury from ALX, while not always sufficiently severe to produce overt diabetes, does appear to induce an hyperresponsiveness to APO-induced hypothermia in a manner similar to that observed in severely diabetic animals.