Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Periaqueductal gray glutamatergic, cannabinoid and vanilloid receptor interplay in defensive behavior and aversive memory formation

Full text
Author(s):
Back, Franklin P. [1] ; Carobrez, Antonio P. [1]
Total Authors: 2
Affiliation:
[1] Univ Fed Santa Catarina, CCB, Dept Farmacol, BR-88049900 Florianopolis, SC - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Neuropharmacology; v. 135, p. 399-411, JUN 2018.
Web of Science Citations: 5
Abstract

Stimulation of the midbrain periaqueductal gray matter (PAG) in humans elicits sensations of fear and impending terror, and mediates predator defensive responses in rodents. In rats, pharmacological stimulation of the dorsolateral portion of the PAG (dIPAG) with N-Methyl-D-Aspartate (NMDA) induces aversive conditioning that acts as an unconditioned stimulus (US). In the present work, we investigated the interplay between the vanilloid TRPVI and cannabinoid CB1 receptors in the NMDA-dIPAG defensive response and in subsequent aversive learning. Rats were subjected to dIPAG NMDA infusion in an olfactory conditioned stimulus (CS) task allowing the evaluation of immediate and long-term defensive behavioral responses during CS presentation. The results indicated that an intermediate dose of NMDA (50 pmol) induced both immediate and long-term effects. A sub-effective dose of NMDA (25 pmol) was potentiated by the TRPV1 receptor agonist capsaicin (CAP, 1 nmol) and the CB1 receptor antagonist, AM251 (200 pmol). CAP (10 nmol) or the combination of CAP (1 nmol) and AM251 (200 pmol) induced long-term effects without increasing immediate defensive responses. The glutamate release inhibitor riluzole (2 or 4 nmol) and the AMPA/kainate receptor antagonist DNQX (2 or 4 nmol) potentiated the immediate effects but blocked the long-term effects. The results showed that immediate defensive responses rely on NMDA receptors, and aversive learning on the fine-tuning of TRPV1, CB1, metabotropic glutamate and AMPA receptors located in pre- and postsynaptic membranes. In conclusion, the activity of the dIPAG determines core affective aspects of aversive memory formation controlled by local TRPV1/CB1 balance. (C) 2018 Elsevier Ltd. All rights reserved. (AU)

FAPESP's process: 12/17626-7 - Cellular and molecular mechanisms involved in the role of atypical neurotransmitters in neuropsychiatric disorders
Grantee:Francisco Silveira Guimaraes
Support Opportunities: Research Projects - Thematic Grants