JPET Introducing ALZET?ew Model 2006 Pump

Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Smith, F. L.
Right arrow Articles by Dewey, W. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Smith, F. L.
Right arrow Articles by Dewey, W. L.

The role of endogenous opioids as mediators of the hypothermic effects of intrathecally administered calcium and calcitonin gene-related peptide in mice

FL Smith, SP Welch, DS Dombrowski and WL Dewey

Department of Pharmacology and Toxicology, Medical College of Virginia/Virginia Commonwealth University, Richmond.

To the authors' knowledge, the effect of i.t. administered calcium on thermoregulation in mice has not been investigated. Calcium administration (i.t.) induced hypothermia in mice. It was found that calcitonin gene-related peptide (CGRP) (i.t.) also produced hypothermia. Because opioids have well documented thermoregulatory effects, the authors evaluated whether the hypothermia induced by calcium and CGRP was the result of the release of opioids. Calcium induced hypothermia at different ambient temperatures (4 degrees C, 22 degrees C and 30 degrees C) in intact mice. Similarly treated spinalized mice maintained body temperature. Using laser Doppler flowmetry, there was a significant increase in blood flow in the tails of calcium-injected mice vs. those of vehicle-injected mice. Both naloxone and naltrindole failed to block the hypothermic effects of calcium (i.t.). Nor-binaltorphimine (i.t.) significantly blocked calcium (i.t.)-induced changes in body temperature. CGRP (i.t.) produced hypothermia for 15 hr postinjection, with the maximum decrease at 3 hr. CGRP induced hypothermia in intact and sham-lesioned mice but not in spinalized mice. CGRP (i.c.v.) also produced hypothermia (onset, 15-min postinjection) followed by the peak effect at 1 hr with recovery to baseline temperature by 2 hr. Subthreshold doses of calcium and CGRP given in combination produced greater than additive hypothermia. The hypothermic effects of CGRP were reversed by naloxone, naltrindole and nor-binaltorphimine. CGRP produced significant hypothermia in both morphine-tolerant and nontolerant mice. Chronic administration of CGRP in nontolerant and morphine-tolerant mice did not alter hypothermia after pretreatment with CGRP (i.t.).(ABSTRACT TRUNCATED AT 250 WORDS)

Volume 266, Issue 3, pp. 1407-1415, 09/01/1993
Copyright © 1993 by American Society for Pharmacology and Experimental Therapeutics






Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
All ASPET Journals Molecular Pharmacology Pharmacological Reviews
Molecular Interventions Drug Metabolism and Disposition

Copyright © 1993 by the American Society for Pharmacology and Experimental Therapeutics.