THE EFFECTS OF CHRONIC AMPHETAMINE TREATMENT ON PRENATAL ETHANOL-INDUCED CHANGES IN DOPAMINE-RECEPTOR FUNCTION - ELECTROPHYSIOLOGICAL FINDINGS

The sensitivity of dopamine (DA) receptors in the mesoaccumbens DA sys tem was investigated with extracellular recording and microiontophores is techniques in adult rats that received prenatal ethanol exposure an d chronic postnatal amphetamine treatment. Pregnant rats were fed with a liquid diet containing 0 or 35% ethanol-derived calories from gesta tion day 6 to 20. An ad libitum group received laboratory chow and wat er. Off-spring were injected with amphetamine (2 mg/kg/day s.c.) or sa line from postnatal day 22 to 10- to 12-months of age. Electrophysiolo gical recording procedures were performed 16 to 24 hr after the last a mphetamine injection. A supersensitivity of somatodendritic DA autorec eptors in the ventral tegmental area was observed in animals exposed p renatally to ethanol. This prenatal ethanol exposure-induced supersens itivity was not observed after postnatal amphetamine treatment. In con trol animals, postnatal amphetamine treatment did not affect the sensi tivity of somatodendritic DA autoreceptors. The sensitivity of D-1 DA receptors in the nucleus accumbens was reduced by prenatal ethanol exp osure. Postnatal amphetamine treatment reduced D-1 DA receptor sensiti vity in control animals, but not in animals exposed prenatally to etha nol. Neither prenatal ethanol treatment nor postnatal amphetamine trea tment altered the sensitivity of D-2 DA receptors in the nucleus accum bens. There were no differences between the ad libitum and 0% ethanol- derived calorie groups, indicating undernutrition did not affect DA re ceptor function. These results show that prenatal ethanol exposure alt ered DA receptor function in the mesoaccumbens DA system in adult anim als. Furthermore, postnatal amphetamine treatment was able to eliminat e the supersensitivity of somatodendritic DA autoreceptors in prenatal ethanol-exposed animals.