Faculty Collaboration Database

Antinociception produced by mu opioid receptor activation in the amygdala is partly dependent on activation of mu opioid and neurotensin receptors in the ventral periaqueductal gray. Brain Res 2000 May 19;865(1):17-26

Date

05/18/2000

Pubmed ID

10814729

DOI

10.1016/s0006-8993(00)02179-x

Scopus ID

2-s2.0-0034685954 (requires institutional sign-in at Scopus site)   79 Citations

Abstract

Exposure to stressful or fear-inducing environmental stimuli activates descending antinociceptive systems resulting in a decreased pain response to peripheral noxious stimuli. Stimulating mu opioid receptors in the basolateral nucleus of the amygdala (BLA) in anesthetized rats produces antinociception that is similar to environmentally induced antinociception in awake rats. Recent evidence suggests that both forms of antinociception are mediated via projections from the amygdala to the ventral periaqueductal gray (PAG). In the present study, we examined the types of neurochemicals released in the ventral PAG that may be important in the expression of antinociception produced by amygdala stimulation in anesthetized rats. Microinjection of a mu opioid receptor agonist into the BLA resulted in a time dependent increase in tail flick latency that was attenuated by preadministration of a mu opioid receptor or a neurotensin receptor antagonist into the ventral PAG. Microinjection of a delta(2) opioid receptor antagonist or an NMDA receptor antagonist into the ventral PAG was ineffective. These findings suggest that amygdala stimulation produces antinociception that is mediated in part by opioid and neurotensin release within the ventral PAG.

Author List

Tershner SA, Helmstetter FJ

Author

Fred Helmstetter PhD Professor in the Psychology / Neuroscience department at University of Wisconsin - Milwaukee

MESH terms used to index this publication - Major topics in bold

Amygdala
Analgesics, Opioid
Animals
Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
Male
Naltrexone
Narcotic Antagonists
Neural Pathways
Neurons
Neurotensin
Nociceptors
Pain
Peptides
Periaqueductal Gray
Rats
Rats, Long-Evans
Receptors, N-Methyl-D-Aspartate
Receptors, Neurotensin
Receptors, Opioid, delta
Receptors, Opioid, mu
Time Factors
Valine