title: Noradrenaline microinjected into the dorsal periaqueductal gray matter causes anxiolytic-like effects in rats tested in the elevated T-maze.
abstract: OBJECTIVE
  The dorsal periaqueductal gray matter (dPAG) is involved in the integration of behavioral and cardiovascular responses caused by fear and anxiety situations. Some studies suggest an involvement of noradrenergic neurotransmission in the dPAG in anxiety modulation, however, there is no evidence about its role in panic attacks. The goal of this work was to study the effect of NA microinjection in dPAG in rats submitted to the elevated T-maze (ETM).
  
  
  METHODS
  Male Wistar had a cannula implanted in the PAG where it was injected NA in the doses of 1, 3, 15, 45nmol/50nl or artificial cerebrospinal fluid previous the ETM test.
  
  
  RESULTS
  NA intra-dPAG decreased inhibitory avoidance behavior in the ETM without changing escape, indicating only an anxiolytic-like effect. Furthermore, the microinjection of NA did not change the general exploratory activity of the animals submitted to the open field test, suggesting that the anxiolytic-like effect is not due to an increase in exploratory activity.
  
  
  CONCLUSIONS
  The results indicate an involvement of noradrenergic neurotransmission in the dPAG in defensive reactions associated with generalized anxiety, but not as main mechanisms for the panic, in rats submitted to the elevated T-maze providing support for other research aimed at improving the treatment of generalized anxiety.
authors.affiliation: Department of Physiological Sciences, Center of Biological Sciences, State University of Londrina, Londrina, PR, Brazil.
authors.forename: Viviane Batista
authors.initials: VB
authors.lastname: Estrada
authors.affiliation: Department of Physiological Sciences, Center of Biological Sciences, State University of Londrina, Londrina, PR, Brazil.
authors.forename: Natália Kimie
authors.initials: NK
authors.lastname: Matsubara
authors.affiliation: Research Centre on Health Sciences, University of Northern Parana (UNOPAR), Londrina, PR, Brazil.
authors.forename: Marcus Vinicius
authors.initials: MV
authors.lastname: Gomes
authors.affiliation: Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Fernando Morgan Aguiar
authors.initials: FM
authors.lastname: Corrêa
authors.affiliation: Department of Physiological Sciences, Center of Biological Sciences, State University of Londrina, Londrina, PR, Brazil. Electronic address: pelosigg@gmail.com.
authors.forename: Gislaine Garcia
authors.initials: GG
authors.lastname: Pelosi
mesh_terms: D000818:Animals; D014151:Anti-Anxiety Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001007:Anxiety / Q000188:drug therapy / Q000523:psychology; D001008:Anxiety Disorders / Q000188:drug therapy / Q000523:psychology; D004305:Dose-Response Relationship, Drug; D004924:Escape Reaction / Q000187:drug effects; D005106:Exploratory Behavior / Q000187:drug effects; D008297:Male; D008845:Microinjections; D009638:Norepinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D010487:Periaqueductal Gray; D051381:Rats; D017208:Rats, Wistar; D013566:Sympathomimetics / Q000008:administration & dosage / Q000494:pharmacology*; D009435:Synaptic Transmission / Q000187:drug effects
chemical_list: D014151:Anti-Anxiety Agents; D013566:Sympathomimetics; D009638:Norepinephrine
keywords: Anxiety; Elevated T-maze; Noradrenaline; Periaqueductal gray matter