Effect of nicotine and nicotinic receptor agonists on latent inhibition in the rat.

摘要: The present experiments assessed the influence of nicotinic cholinergic receptors on latent inhibition (LI), which is decrement in Pavlovian conditioning resulting from extensive preexposure to a conditioned stimulus (CS). LI was within emotional response paradigm involving three phases: [either 0 (nonpreexposed) or 60 (preexposed) presentations sec tone], (two-tone, 0.6 mA; 0.5-sec footshock pairings) and test (assessment CS-induced suppression lever press responding). obtained that untreated preexposed-animals displayed less compared nonpreexposed controls. Administration nicotine (0.4 mg/kg i.p.) augmented when administered during conditioning. In addition, enhanced preexposure, suggesting can enhance ability an animal filter irrelevant stimuli. agonists cytisine (5 mg/kg) lobeline (10 also LI. Nicotine did not behavior animals, nicotine's effect specific mechanisms mediating antagonists hexamethonium mecamylamine reversed enhancement Finally, found depend upon CS parameters; attenuated, rather than enhanced, observed after 40 5-sec CS. These results suggest stimulation either amplify curtail efficacy involved filtering stimuli further cognitive processing direction this modulation depends parameters.