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Titolo:
EFFECT OF NICOTINE AND NICOTINIC RECEPTOR AGONISTS ON LATENT INHIBITION IN THE RAT
Autore:
ROCHFORD J; SEN AP; QUIRION R;
Indirizzi:
MCGILL UNIV,DOUGLAS HOSP,RES CTR,DEPT PSYCHIAT,6875 LASALLE BLVD VERDUN PQ H4H 1R3 CANADA
Titolo Testata:
The Journal of pharmacology and experimental therapeutics
fascicolo: 3, volume: 277, anno: 1996,
pagine: 1267 - 1275
SICI:
0022-3565(1996)277:3<1267:EONANR>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACETYLCHOLINE-RELEASE; CHRONIC AMPHETAMINE; BRAIN; MEMORY; PREEXPOSURE; ATTENTION; STIMULUS; MODEL; HEXAMETHONIUM; MECAMYLAMINE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
50
Recensione:
Indirizzi per estratti:
Citazione:
J. Rochford et al., "EFFECT OF NICOTINE AND NICOTINIC RECEPTOR AGONISTS ON LATENT INHIBITION IN THE RAT", The Journal of pharmacology and experimental therapeutics, 277(3), 1996, pp. 1267-1275

Abstract

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

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Documento generato il 07/04/20 alle ore 03:10:35