Effects of the combined administration of the 5-HT3 antagonist MDL 72222 and ethanol on conditioning in the periadolescent and adult rat.
The effects of acute ethanol and treatment with the 5-HT3 antagonist MDL 72222 on conditioning of a visual pattern discrimination and an olfactory context were examined in periadolescent (35-38-day-old) and adult (60-70-day-old) rats. In Experiment 1, the effects of acute ethanol exposure on conditioning of a visual pattern discrimination (horizontal vs. vertical black and white stripes) and an olfactory context were investigated. The results indicated that a moderate dose of ethanol, 2 g/kg, disrupted conditioning at both ages to the visual stimulus but not to the olfactory context in which conditioning occurred. This may reflect differential susceptibility of target and contextual learning to the effects of ethanol, or might instead confirm previous suggestions that the visual system is more susceptible than the olfactory system to the effects of acute ethanol exposure. The effects of 5.0 and 10.0 mg/kg MDL 72222 on the ethanol-induced impairment in pattern discrimination conditioning were examined in Experiment 2. Pretreatment with these doses of MDL 72222 did not reverse the cognitive impairments produced by acute ethanol exposure at either age. However, MDL 72222 pretreatment attenuated the hyperlocomotion evident in ethanol-treated male and female periadolescents and adult females, as indexed by the number of crossovers during the preference test. Thus, MDL 72222 does not appear to ameliorate the cognitive impairment induced by acute ethanol exposure, although the antagonist was observed to attenuate ethanol-induced hyperlocomotion in the same test situation.
Rajachandran
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Department of Psychology, Binghamton University, NY 13902-6000.
Spear
N E
NE
Spear
L P
LP
D000375:Aging / Q000523:psychology*; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D004193:Discrimination Learning / Q000187:drug effects; D000431:Ethanol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010364:Pattern Recognition, Visual; D051381:Rats; D017207:Rats, Sprague-Dawley; D012702:Serotonin Antagonists / Q000494:pharmacology*; D012903:Smell / Q000187:drug effects; D014326:Tropanes / Q000494:pharmacology*
D012702:Serotonin Antagonists; D014326:Tropanes; D000431:Ethanol; C042253:bemesetron