Mechanisms of the Analgesic Effect of Corticotropin-Releasing Factor in Conscious Rats.
Summary of "Mechanisms of the Analgesic Effect of Corticotropin-Releasing Factor in Conscious Rats."
We report here our studies of the contribution of the hypothalamo-hypophyseal-adrenocortical system (HHACS) and opioid system to the analgesic effect of corticotropin-releasing factor (CRF) in conscious rats exposed to thermal stimuli. Two methodological approaches were used: 1) blockade of the functional activity of the HHACS by administration of hydrocortisone at a pharmacological dose one week before experiments; 2) blockade of glucocorticoid receptors with the glucocorticoid receptor antagonist RU38486. The contribution of the opioid system was studied by blockade of opioid receptors with their antagonist naltrexone. Blockade of opioid receptors completely eliminated the analgesic effect of CRF, blockade of the functional activity of the HHACS decreased it, and blockade of glucocorticoid receptors increased the effect. These data provide evidence that the analgesic effect of CRF in conscious rats exposed to a thermal stimulus is mediated by an opioid-associated mechanism. The actions of opioids on pain sensitivity may be modulated by glucocorticoid hormones.
Affiliation
Experimental Endocrinology Laboratory, I. P. Pavlov Institute of Physiology, Russian Academy of Sciences, 6 Makarov Bank, 199034, St. Petersburg, Russia, Yarni60@mail.ru.
Journal Details
This article was published in the following journal.
Name: Neuroscience and behavioral physiology
ISSN: 1573-899X
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/21611702
- DOI: http://dx.doi.org/10.1007/s11055-011-9444-3
Medical and Biotech [MESH] Definitions
Receptors, Corticotropin-releasing Hormone
Cell surface proteins that bind corticotropin-releasing hormone with high affinity and trigger intracellular changes which influence the behavior of cells. The corticotropin releasing-hormone receptors on anterior pituitary cells mediate the stimulation of corticotropin release by hypothalamic corticotropin releasing factor. The physiological consequence of activating corticotropin-releasing hormone receptors on central neurons is not well understood.
Dextropropoxyphene
A narcotic analgesic structurally related to METHADONE. Only the dextro-isomer has an analgesic effect; the levo-isomer appears to exert an antitussive effect.
Alfentanil
A short-acting opioid anesthetic and analgesic derivative of FENTANYL. It produces an early peak analgesic effect and fast recovery of consciousness. Alfentanil is effective as an anesthetic during surgery, for supplementation of analgesia during surgical procedures, and as an analgesic for critically ill patients.
Urocortins
Neuropeptides of about 40 amino acids which are structurally similar to CORTICOTROPIN-RELEASING FACTOR. Unlike CRF acting primarily through type 1 CRF RECEPTORS, urocortins signal preferentially through type 2 CRF receptors. Urocortins have wide tissue distribution from fish to mammals, and diverse functions. In mammals, urocortins can suppress food intake, delays gastric emptying, and decreases heat-induced edema.
Defense Mechanisms
Unconscious process used by an individual or a group of individuals in order to cope with impulses, feelings or ideas which are not acceptable at their conscious level; various types include reaction formation, projection and self reversal.
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