title: Nicotine-induced anxiogenic-like behaviours of rats in the elevated plus-maze: possible role of NMDA receptors of the central amygdala.
abstract: The objective of the present study was to investigate the possible role of the N-methyl-D-aspartate (NMDA) receptor system of the central amygdala (CeA) in the anxiogenic-like effect of nicotine. Male Wistar rats with cannulas aimed to the CeA were submitted to the elevated plus-maze (EPM). Intraperitoneal (i.p.) injections of nicotine (0.6 and 0.8 mg/kg) decreased percentage open arm time spent (%OAT) and percentage open arm entries (%OAE), but not locomotor activity, indicating an anxiogenic-like response. Bilateral intra-CeA microinjection of NMDA (0.005-0.1 μ g/rat) decreased %OAT, but not %OAE and locomotor activity. Moreover, intra-CeA microinjection of NMDA (0.05 μ g) with an ineffective dose of nicotine (0.4 mg/kg, i.p.) reduced %OAT and %OAE without effect on locomotor activity. On the other hand, intra-CeA microinjection of the NMDA receptor antagonist D-AP5 (0.05-0.5 μ g/rat) increased both %OAT and %OAE, showing an anxiolytic-like effect of the drug. Co-administration of the same doses of D-AP5 with nicotine (0.6 mg/kg, i.p.) increased %OAT and %OAE, but not locomotor activity. Intra-CeA microinjection of D-AP5 reversed the response induced by NMDA (0.1 μ g/rat) in the EPM. The results may support the possible involvement of glutamate transmission, through NMDA receptors of central amygdala in the anxiogenic-like effect of nicotine in the EPM task.
authors.affiliation: Department of Neuroscience, School of Advanced Medical Technologies and Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. zarinmr@ams.ac.ir
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Zarrindast
authors.forename: Arash
authors.initials: A
authors.lastname: Aghamohammadi-Sereshki
authors.forename: Ameneh
authors.initials: A
authors.lastname: Rezayof
authors.forename: Parvin
authors.initials: P
authors.lastname: Rostami
mesh_terms: D015763:2-Amino-5-phosphonovalerate / Q000031:analogs & derivatives / Q000494:pharmacology; D000679:Amygdala / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D001007:Anxiety / Q000139:chemically induced*; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D016202:N-Methylaspartate / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; C096637:2-amino-5-phosphono-3-pentenoic acid; D016202:N-Methylaspartate; D009538:Nicotine; D015763:2-Amino-5-phosphonovalerate