Prenatal ethanol exposure decreases hippocampal 3H-glutamate binding in 45-day-old rats.
The effect of prenatal ethanol exposure on putative glutamate receptor binding sites in rat brain was studied using radiohistochemical techniques. Pregnant Sprague-Dawley rats were fed a liquid diet containing either 3% or 6% (vol./vol.) ethanol throughout gestation. Pair-fed dams received isocalorically matched liquid diets and a lab chow ad lib group served as control for paired feeding. At 45 days of age, the offspring were sacrificed and their brains analyzed by in vitro 3H-glutamate autoradiography. Compared to pair-fed controls, specific 3H-glutamate binding was reduced by 49-53% in regions of the dorsal hippocampal formation of 45-day-old rats whose mothers consumed either 3% or 6% ethanol diets. Specific 3H-glutamate binding was decreased also in the ventral hippocampal formation, entorhinal and posterior neocortex, but to a less consistent degree and magnitude than in dorsal hippocampal formation of fetal alcohol rats. The reduction in hippocampal 3H-glutamate binding 45 days after prenatal ethanol exposure suggests a long-lasting net decrease in glutamate-mediated excitatory neurotransmission within the hippocampal formation of fetal alcohol rats. This glutamate receptor binding site alteration may be one factor contributing to a decrease in long-term potentiation of hippocampal CA1 pyramidal neurons in fetal alcohol rats. In addition, this alteration may underlie learning and other behavioral deficits associated with functional defects of the hippocampal formation.
Farr
K L
KL
Department of Pharmacology, University of New Mexico School of Medicine, Albuquerque 87131.
Montano
C Y
CY
Paxton
L L
LL
Savage
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DD
D000818:Animals; D001724:Birth Weight / Q000187:drug effects; D000431:Ethanol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D005971:Glutamates / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000187:drug effects* / Q000378:metabolism; D014316:Tritium
D005971:Glutamates; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D014316:Tritium; D000431:Ethanol