Narcotic withdrawal like mouse jumping produced by amphetamine and L-DOPA.

Upward jumping in mice that resembled the narcotic-withdrawal syndrome was produced by a combination of amphetamine (4 mg/kg) and L-DOPA (400 mg/kg) administration. Neither drug alone caused that jumping. Pretreatment with haloperidol (0.16 mg/kg) or pimozide (0.08 mg/kg) but not with phentolamine (10mg/kg) effectively blocked amphetamine-dopa jumping. After DOPA there was an increase in the brain levels of DOPA, dopamine and norepinephrine. Amphetamine, ineffective in itself, enhanced DOPA-induced elevation of brain DOPA and dopamine without affecting brain norepinephrine levels.