Opioid receptors in the prelimbic cortex modulate restraint stress-induced cardiovascular responses in the rat

Author(s)

Fassini, Aline ^[1] ; Scopinho, America A. ^[1] ; Resstel, Leonardo B. M. ^[1] ; Correa, Fernando M. A. ^[1]

Affiliation

^[1] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Pharmacol, BR-14049 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: Neuropharmacology; v. 85, p. 367-374, OCT 2014.
• Web of Science Citations: 6

Abstract

The prelimbic cortex (PL) is involved in the control of behavioral and autonomic responses to stress. The present study aimed to investigate whether opioid neurotransmission in the PL modulates autonomic responses evoked by restraint stress (RS). Bilateral microinjection of 0.03, 0.3 and 3 nmol/100 nL of the nonselective opioid antagonist naloxone into the PL reduced pressure and tachycardiac responses evoked by RS. However, no effects were observed after its injection at doses of 0.003 and 30 nmol/100 nL, thus resulting in an inverted U-shaped dose-inhibition curve. Similar to naloxone, the selective mu-opioid antagonist CTAP, and the selective mu-opioid antagonist nor-BNI, also reduced MAP and HR increases induced by RS when injected into the PL, whereas treatment with the selective delta-opioid antagonist naltrindole did not affect the pressor and tachycardiac response caused by RS. Blockade of opioid neurotransmission in the PL did not affect the fall in tail temperature and increase in body temperature induced by RS. The present results confirm the involvement of PL opioid neurotransmission in the modulation of cardiovascular responses evoked during the exposure to an aversive situation, and suggest that responses observed after the blockade of local opioid receptors is due to alterations in PL neuronal activity. Furthermore, these results suggest that a distinct circuitry is involved in modulation of the sympathetic output to different vascular territories. (C) 2014 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 type: Research Projects - Thematic Grants
• FAPESP's process: 13/00249-9 - Involvement of opioid neurotransmission of the medial amygadala in the mediation of autonomic and hormonal responses evoked by restraint stress in rats
• Grantee: Aline Fassini
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 12/09300-4 - Bed nucleus of the stria terminalis noradrenergic system modulates contextual fear conditionig: possible interaction with CRF and glutamatergic and nitrergic neurotransmission
• Grantee: Leonardo Resstel Barbosa Moraes
• Support type: Regular Research Grants