Effect of NO synthase inhibition on behavioral changes induced by a single administration of methamphetamine.

The present study examined the effects of nitric oxide synthase inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME; 10, 30, 60 mg/kg, i.p.) on behavioral changes induced by a single administration of methamphetamine (MA) (3.22 and 0.805 mg free base/kg, s.c.). MA increased locomotion-stereotypy rating scores and motor activity counts measured by an infrared sensor. L-NAME administered prior to MA significantly decreased the level of locomotion stereotypy rating and motor activity induced by MA. An inactive optical isomer, N omega-nitro-D-arginine methyl ester (D-NAME) had no effects on MA-induced behavioral changes. The results suggest that NO synthesis is involved in the full expression of behavioral effects of MA.