GENOTYPIC DIFFERENCES IN LOCOMOTOR STIMULATION AND DOPAMINERGIC ACTIVITY FOLLOWING ACUTE ETHANOL ADMINISTRATION

The effects of increasing doses of ethanol on locomotor activity and o n the metabolism of dopamine (DA) in the limbic forebrain and in the s triatum of CBA, C57, and NMRI mice were studied. In NMRI mice, low dos es of ethanol produced locomotor stimulation which was followed by inh ibition of locomotor activity at higher doses. In C57 and CBA animals, ethanol caused only reduction of locomotor activity. A low dose of et hanol (2.25 g/kg, i.p.) produced a significant enhancement of the rele ase of dopamine (measured as the ratio DOPAC/DA) in limbic brain struc tures of all animals with no corresponding effect in the striatum. A h igh dose of ethanol (4.5 g/kg, i.p.) significantly increased the DOPAC /DA ratio both in the limbic forebrain and in the striatum of all anim als. The significance of these behavioral and biochemical observations with regard to genetic aspects of the role of DA in the stimulatory/r einforcing properties of ethanol and to previously observed genetic di fferences in other neurotransmitter systems, especially GABA and gluta mate, is discussed.