FREE-RADICALS AND TASTE-AVERSION LEARNING IN THE RAT - NITRIC-OXIDE, RADIATION AND DOPAMINE

1. Injection of sodium nitroprusside (SNP) or N-tert-butyl-alpha-pheny l nitrone (PEN) produces a conditioned taste aversion (CTA) in rats. T he CTA can be prevented by pretreatment with N-omega-nitro-L-arginine (L-NArg), indicating that nitric oxide (NO) is a behaviorally toxic co mpound. 2. Radiation-induced CTA learning is not affect by pretreatmen t with L-NArg or by preexposure to PEN, indicating that a radiation-st imulated formation of NO does not mediate the toxic effects of radiati on on behavior. 4. Pretreating rats with the dopamine antagonist halop eridol prevented the acquisition of the CTA produced by SNP and attenu ated, but did not eliminate, the PEN-induced CTA. Preexposure to the d opamine agonist amphetamine, attenuated a PBN-induced CTA, although PE N preexposure did not affect an amphetamine-induced CTA. 5. The result s are interpreted as supporting a role for NO-stimulated dopamine rele ase in the acquisition of taste aversions following injection of SNP o r PEN.