title: Effect of dopamine and serotonin receptor antagonists on fencamfamine-induced abolition of latent inhibition.
abstract: The purpose of this investigation was to verify the role of dopamine and serotonin receptors in the effect of fencamfamine (FCF) on latent inhibition. FCF is a psychomotor stimulant with an indirect dopaminergic action. Latent inhibition is a model of attention. Latent inhibition is blocked by dopaminergic agents and facilitated by dopamine receptor agonists. FCF has been shown to abolish latent inhibition. The serotonergic system may also participate in the neurochemical mediation of latent inhibition. The selective dopamine D(1) receptor antagonist SCH 23390 (7-chloro-3-methyl-1-phenyl-1,2,4,5-tetrahydro-3-benzazepin-8-ol), D(2) receptor antagonists pimozide (PIM) and methoclopramide (METH), and serotonin 5-HT(2A/C) receptor antagonist ritanserin (RIT) were used in the present study. Latent inhibition was evaluated using a conditioned emotional response procedure. Male Wistar rats that were water-restricted were subjected to a three-phase procedure: preexposure to a tone, tone-shock conditioning, and a test of the effect of the tone on licking frequency. All of the drugs were administered before the preexposure and conditioning phases. The results showed that FCF abolished latent inhibition, and this effect was clearly antagonized by PIM and METH and moderately attenuated by SCH 23390. At the doses used in the present study, RIT pretreatment did not affect latent inhibition and did not eliminate the effect of FCF, suggesting that the FCF-induced abolition of latent inhibition is not mediated by serotonin 5-HT(2A/C) receptors. These results suggest that the effect of FCF on latent inhibition is predominantly related to dopamine D(2) receptors and that dopamine D(2) receptors participate in attention processes.
authors.affiliation: Department of Psychology, Laboratory of Experimental Psychology, CFCH, Federal University of Pernambuco, Recife 50670-901, PE, Brazil. cilenelabpex@yahoo.com.br
authors.forename: Cilene Rejane Ramos Alves
authors.initials: CR
authors.lastname: de Aguiar
authors.forename: Marlison José Lima
authors.initials: MJ
authors.lastname: de Aguiar
authors.forename: Roberto
authors.initials: R
authors.lastname: DeLucia
authors.forename: Maria Teresa Araujo
authors.initials: MT
authors.lastname: Silva
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects*; D004298:Dopamine / Q000378:metabolism; D018492:Dopamine Antagonists / Q000494:pharmacology*; D008297:Male; D009636:Norbornanes / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011954:Receptors, Dopamine / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D012702:Serotonin Antagonists / Q000494:pharmacology*
chemical_list: D000697:Central Nervous System Stimulants; D018492:Dopamine Antagonists; D009636:Norbornanes; D011954:Receptors, Dopamine; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; C020900:fencamfamine; D004298:Dopamine