Calcitonin depresses amphetamine-induced locomotor activity.

Synthetic salmon calcitonin (sCT), given subcutaneously (6.4 micrograms/kg) or intracerebroventricularly (ICV, 30-600 ng), depressed amphetamine-induced locomotor activity in rats by more than 50%. ICV injection of sCT, either three hours or immediately before intraperitoneal amphetamine (1-3 mg/kg), significantly reduced the amphetamine-induced activity. In the absence of amphetamine, sCT had no effect on locomotor activity during the first 100 minutes after treatment. These results show sCT can act centrally to modify drug-induced behavior and may be related to reports of calcitonin receptors and calcitonin-like peptides in the brain.