Stereotyped behavior and diabetes mellitus in rats: reduced behavioral effects of amphetamine and apomorphine and reduced in vivo brain binding of [3H]spiroperidol.

Rats made diabetic with streptozotocin showed decreased stereotyped behaviors following administration of amphetamine or apomorphine. Spontaneous activity in an open field was lower in diabetics than in controls, but a low dose of apomorphine produced equivalent fractional decreases in activity in both groups. In vivo accumulation of amphetamine and apomorphine was generally similar in both groups: Reduced tissue access did not appear to be responsible for the decreased behavioral effects of these agents. The in vivo accumulation of spiroperidol in several brain regions was generally less in diabetics than in controls. These data are discussed in terms of altered catecholamine biochemistry and behavior in diabetics.