Dopaminergic influence on withdrawal jumping behavior in morphine dependent mice

Abrupt withdrawal jumping behavior in morphine dependent mice is accompanied by a decrease in brain dopamine turnover and an increase in brain dopamine level which parallel strain differences in jumping incidence. Both naloxone precipitated and abrupt withdrawal jumping behavior are inhibited in a dose dependent manner by the dopamine agonist apomorphine. A cataleptic dose of the dopaminergic antagonist, haloperidol, does not block naloxone precipitated jumping, but does significantly block the inhibition by apomorphine. These findings indicate that there may be a decreased release of dopamine in the brain during the expression of withdrawal jumping behavior and that dopaminergic activation may be inhibitory to this behavior.