The effects of in utero ethanol administration on the electrophysiological activity of rat nigrostriatal dopaminergic neurons.
Iontophoresis and single-unit extracellular recording techniques were utilized to study the effects of in utero ethanol administration on nigrostriatal dopaminergic (NSDA) neurons in adult rats. Pregnant Sprague-Dawley rats consumed an ethanol-containing liquid diet providing 0%, 17.5%, or 35% ethanol-derived calories (EDC) from gestation day 8 until parturition. A separate group was fed standard rat chow as an ad lib, diet control. The dose-response curves of intravenously administered apomorphine on the spontaneous activity of NSDA neurons were shifted to the right in animals exposed to a liquid diet containing 17.5% or 35% EDC compared to 0% EDC or ad lib. control groups. The responsiveness of NSDA neurons to microiontophoretic application of the D-2 DA receptor agonist, quinpirole, was not altered following in utero ethanol exposure. These results suggest that in utero ethanol exposure may produce a down-regulation in the function of DA receptors distinct from the somatodendritic impulse-regulating D-2 autoreceptors. The firing pattern of NSDA neurons was also found to be altered after in utero ethanol exposure. There was a dissociation between the firing rate and burst activity in neurons that displayed burst-firing patterns in animals with in utero ethanol exposure. These observations agree with biochemical and behavioral studies that in utero ethanol exposure produces a long-lasting effect on the development of electrophysiological and pharmacological characteristics of midbrain DA systems in adulthood.
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Department of Psychiatry, Wayne State University School of Medicine, Detroit, MI 48201.
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D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D003342:Corpus Striatum / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism; D004594:Electrophysiology; D004873:Ergolines / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D007478:Iontophoresis; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D019257:Quinpirole; D051381:Rats; D017207:Rats, Sprague-Dawley; D013378:Substantia Nigra / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
D004873:Ergolines; D019257:Quinpirole; D000431:Ethanol; D001058:Apomorphine; D004298:Dopamine