title: Bed nucleus of the stria terminalis NMDA receptors and nitric oxide modulate contextual fear conditioning in rats.
abstract: The bed nucleus of the stria terminalis (BNST) modulates anxiety-like responses, including conditioned emotional responses. Evidence suggests that glutamatergic neurotransmission in the BNST plays a role in the modulation of defensive responses. However, little is known about the involvement of glutamate NMDA receptor activation within the BNST, and its resultant increase in nitric oxide (NO) levels, in the expression of contextual fear conditioning (CFC). We investigated whether the antagonism of NMDA receptors or the reduction of NO levels in the BNST would attenuate behavioral and autonomic responses (i.e. increase in arterial pressure and heart rate, and decrease in tail cutaneous temperature) of rats submitted to a CFC paradigm. Intra-BNST infusion of AP7, an NMDA receptor antagonist, attenuated both behavioral and autonomic changes induced by CFC. Similar results were observed with NPLA and c-PTIO, an nNOS inhibitor and an NO scavenger, respectively. A positive correlation between BNST NO levels and the time spent in freezing behavior was also observed for animals submitted to the CFC. These findings indicate that the expression of CFC involves a facilitation of BNST NMDA receptor-NO signaling. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'.
authors.affiliation: Department of Pharmacology, School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Sara C
authors.initials: SC
authors.lastname: Hott
authors.affiliation: Department of Pharmacology, School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Felipe V
authors.initials: FV
authors.lastname: Gomes
authors.affiliation: Department of Pharmacology, School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Daniela L
authors.initials: DL
authors.lastname: Uliana
authors.affiliation: Department of Psychiatric Nursing and Human Sciences, College of Nursing of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Gabriel T
authors.initials: GT
authors.lastname: Vale
authors.affiliation: Department of Psychiatric Nursing and Human Sciences, College of Nursing of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Tirapelli
authors.affiliation: Department of Pharmacology, School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil. Electronic address: leoresstel@yahoo.com.br.
authors.forename: Leonardo B M
authors.initials: LB
authors.lastname: Resstel
mesh_terms: D000818:Animals; D062186:Arterial Pressure; D001341:Autonomic Nervous System / Q000502:physiology; D003214:Conditioning, Classical / Q000502:physiology; D005239:Fear / Q000502:physiology*; D006339:Heart Rate; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology*; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000502:physiology*; D012686:Septal Nuclei / Q000378:metabolism / Q000502:physiology*
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D009569:Nitric Oxide; D052248:Nitric Oxide Synthase Type I
keywords: Autonomic responses; Cardiovascular system; Conditioned emotional responses; Freezing behavior; Glutamate