[Rotational behavior induced by methamphetamine and cocaine in rats with unilateral 6-hydroxydopamine lesions of the nigrostriatal dopamine system].

The purpose of this study was to compare the ability of intravenously administered methamphetamine and cocaine to facilitate dopaminergic transmission, based on the ability of these drugs to induce rotational behavior in rats with unilateral 6-hydroxydopamine lesions of the substantia nigra. The doses of methamphetamine and cocaine ranged from 0.25 mg/kg to 4 mg/kg which was equivalent to 50% of the minimum dose which caused convulsion. Methamphetamine induced more marked ipsilateral rotational behavior than did cocaine. The present results suggest that methamphetamine produces longer duration of the facilitation of dopaminergic transmission both in the nucleus accumbens and in the striatum than does cocaine.