Differential effect of buspirone and diazepam on negative contrast in one-way avoidance learning.
The main aim of the present work was to investigate the effect of buspirone, a 5-HT1A receptor agonist, on successive negative contrast in one-way avoidance learning. Successive negative contrast was induced by shifting rats from a large reward (30 s spent in the safe compartment) to a small reward (1 s). Acute administration of buspirone (0.25, 0.5, 0.75 and 1.0 mg/kg i.p.) did not attenuate the contrast effect, as opposed to that observed for diazepam (1 mg/kg i.p.). The highest dose of buspirone used, however, did interfere with the learning of the avoidance response itself. Chronic buspirone (20 days, 0.5 and 0.75 mg/kg i.p.) did not have any effect on successive negative contrast either. Overall, these results could suggest that the 5-HT1A receptor is not involved in the negative contrast effect studied, quite different to that observed for the gamma-aminobutyric acid (GABA) system. The findings are compared to results obtained with animal models selectively sensitive to some anxiolytic drugs, as are the so-called 'conflict models'.
Torres
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Departamento de Psicología Experimental y Fisiología del Comportamiento, Universidad de Granada, Spain.
Morales
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Cándido
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Maldonado
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D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001362:Avoidance Learning / Q000187:drug effects*; D002065:Buspirone / Q000008:administration & dosage / Q000494:pharmacology*; D003975:Diazepam / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D007274:Injections, Intraperitoneal; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D018079:Receptors, GABA / Q000187:drug effects / Q000378:metabolism
D014151:Anti-Anxiety Agents; D018079:Receptors, GABA; D003975:Diazepam; D002065:Buspirone