Dopamine receptor in the streptozotocin-induced diabetic rats

The abnormalities of central dopamine receptors were examined in streptozotocin (STZ, 60 mg/kg)-induced diabetic rats by using apomorphine (APO)-induced changes of locomotor activity. Chronic hyperglycemia (BG greater than 200 mg/dl) suppressed locomotor activity. Decreased locomotor activity was observed in both intact control and diabetic rats after administration of small dose of APO (0.05 mg/kg). On the other hand, diabetic rats showed a lower peak and response than controls, after large dose of APO (0.50 mg/kg) treatment. Moreover, no significant increase of locomotor activity activity was observed in the diabetic rats, while a significant increase of locomotor activity was observed in the control rats. The present data obtained herein suggest that the disturbances in the central dopaminergic postsynaptic receptors may be related to the decreased locomotor activity in STZ-induced diabetic rats.