Noradrenaline microinjected into the dorsal periaqueductal gray matter causes anxiolytic-like effects in rats tested in the elevated T-maze

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...

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Bibliographic Details
Published in:Life sciences (1973) 2016-05, Vol.152, p.94-98
Main Authors: Estrada, Viviane Batista, Matsubara, Natália Kimie, Gomes, Marcus Vinicius, Corrêa, Fernando Morgan Aguiar, Pelosi, Gislaine Garcia
Format: Article
Language:English
Subjects:
Animals
Anti-Anxiety Agents - administration & dosage
Anti-Anxiety Agents - pharmacology
Anxiety
Anxiety - drug therapy
Anxiety - psychology
Anxiety Disorders - drug therapy
Anxiety Disorders - psychology
Dose-Response Relationship, Drug
Elevated T-maze
Escape Reaction - drug effects
Exploratory Behavior - drug effects
Male
Microinjections
Noradrenaline
Norepinephrine - administration & dosage
Norepinephrine - pharmacology
Periaqueductal Gray
Periaqueductal gray matter
Rats
Rats, Wistar
Sympathomimetics - administration & dosage
Sympathomimetics - pharmacology
Synaptic Transmission - drug effects
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Summary: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). 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. 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. 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.
ISSN:0024-3205
1879-0631
DOI:10.1016/j.lfs.2016.03.011