Inhibition of nitric oxide synthesis reduces intravenous cocaine self-administration in the rat.

The effects of a blockade of nitric oxide synthesis were studied in rats trained to self-administer cocaine intravenously. Pretreatment with Ng-nitro-1-arginine methyl ester (l-NAME; 10-50 mg/kg, intraperitoneally, twice daily for 4 days), significantly and dose-dependently suppressed the maintenance of intravenous cocaine self-administration and the absolute reward magnitude of cocaine. These results suggest that nitric oxide may play a role in cocaine abuse and dependence.