AMYGDALA DOPAMINE LEVELS ARE MARKEDLY ELEVATED AFTER SELF-ADMINISTRATION BUT NOT PASSIVE-ADMINISTRATION OF COCAINE

The influence of cocaine on rat brain monoaminergic neurotransmitters (dopamine, serotonin, noradrenaline) and their metabolites, and on bin ding of [H-3]WIN 35,428 and [H-3]GBR 12,935 to the dopamine transporte r was measured after 4 weeks of cocaine exposure. Cocaine (mean daily dose 9.25 +/- 0.48 mg/kg) was self-administered (responders) or passiv ely received (yoked) during sessions which lasted for 1 h per day. As compared with the controls, mean dopamine and serotonin levels were si gnificantly elevated ( + 107% and + 47%, respectively) in amygdala of responders, but not of yoked rats, sacrificed 1 h after the last cocai ne session, Dopamine and metabolite levels were normal in all other br ain areas examined, including striatum, nucleus accumbens and medial p refrontal cortex, at both 1 h and 4 weeks withdrawal from cocaine. [H- 3]WIN 35,428 and [H-3]GBR 12,935 binding were unaltered after cocaine exposure. These data provide additional support for the involvement of the amygdala in the acquisition of drug seeking behavior associated w ith cocaine self-administration.