title: Serotonin in anxiety and panic: contributions of the elevated T-maze.
abstract: The elevated T-maze (ETM) was developed to test the hypothesis that serotonin (5-HT) plays an opposing role in the regulation of defensive behaviors associated with anxiety and panic. This test allows the measurement in the same rat of inhibitory avoidance acquisition, related to generalized anxiety disorder, and of one-way escape, associated with panic disorder. The evidence so far reported with the ETM supports the above hypothesis and indicates that: (1) whereas 5-HT neurons located at the dorsal raphe nucleus are involved in the regulation of both inhibitory avoidance and escape, those of the median raphe nucleus are primarily implicated in the former task; (2) facilitation of 5-HT1A- and 5-HT2A-mediated neurotransmission in the dorsal periaqueductal gray (dPAG) is likely to mediate the panicolytic drug action; (3) stimulation of 5-HT2C receptors in the basolateral amygdala increases anxiety and is implicated in the anxiogenesis caused by short-term administration of antidepressant drugs, and (4) 5-HT1A and the μ-opioid receptors work together in the dPAG to modulate escape or panic attacks. These last results point to the possible benefits of adjunctive opioid therapy for panic patients resistant to antidepressants that act on 5-HT neurotransmission.
authors.affiliation: Department of Pharmacology, Medical School of Ribeirão Preto, University of São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, SP 14090-900, Brazil. Electronic address: zangross@fmrp.usp.br.
authors.forename: Hélio
authors.initials: H
authors.lastname: Zangrossi
authors.affiliation: Institute of Neuroscience and Behavior - IneC, Ribeirão Preto, SP, Brazil.
authors.forename: Frederico G
authors.initials: FG
authors.lastname: Graeff
mesh_terms: D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology / Q000627:therapeutic use; D001007:Anxiety / Q000188:drug therapy / Q000378:metabolism*; D004195:Disease Models, Animal; D006801:Humans; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology*; D010200:Panic / Q000502:physiology*; D051381:Rats; D012701:Serotonin / Q000378:metabolism*
chemical_list: D000928:Antidepressive Agents; D012701:Serotonin
keywords: Animal model; Antidepressants; Anxiety; Panic; Pathophysiology; Serotonin