[Effect of dopamine intracerebrally injected by the Valzelli method on methamphetamine-stereotypy and hypermotility]

In this investigation, the effect of methamphetamine (MAPT) was examined on stereotyped licking and biting and locomotor activity in reserpinized rats which were administered dopamine (DA) intracerebrally. Twenty-four hours after the treatment of reserpine (RE, 1.25 mg/kg ip) or 0.9% saline solution. Wistar male rats received DA (300 micrograms/rat ic) or 0.9% saline solution (5 microliters/rat ic) by Valzelli's method and then 10 min later MAPT (3 mg/kg or 10 mg/kg ip) Stereotyped biting was induced by each dose of MAPT in reserpinized rats. This was suppressed, however, in reserpinized rats given DA. Stereotyped licking was induced by MAPT (10 mg/kg ip) in saline-treated rats. This score did not differ in comparison with the case given DA. Hypermotility was shown by each dose of MAPT in reserpinized and saline-treated rats. This was particularly potentiated in reserpinized rats given DA before the MAPT (10 mg/kg ip), but not any cases of saline-treated rats combined with DA. It is suggested that MAPT-induced stereotyped licking and biting are suppressed in reserpinized rats given DA in a high dose while MAPT-induced hypermotility is potentiated in rats treated as above.