Hypothermic effect of D-Ala-deltorphin II, a selective delta opioid receptor agonist.
The natural heptapeptide D-Ala-deltorphin II, the most selective agonist for delta-receptors currently available, was used to study the role of brain delta opioid receptors in the control of body temperature. In rats placed in a cold ambient temperature (4 degrees C), intracerebroventricular injections of D-Ala-deltorphin II produced a significant hypothermia. In animals at an ambient temperature of 22 degrees C, only the highest dose employed induced a slight fall in body temperature. At a warm temperature (34 degrees C), D-Ala-deltorphin II induced no significant changes in body temperature. D-Ala-deltorphin II-induced hypothermia, unaffected by naloxone, was significantly reduced by the selective delta receptor antagonist naltrindole. These findings indicate that D-Ala-deltorphin II produces its hypothermic effects at a supraspinal delta receptor, and support the involvement of delta receptors in central control of body temperature.
Broccardo
M
M
Institute of Pharmacology III, University La Sapienza, Rome, Italy.
Improta
G
G
D000818:Animals; D001831:Body Temperature / Q000187:drug effects*; D007211:Indoles / Q000494:pharmacology; D007276:Injections, Intraventricular; D009019:Morphinans / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009271:Naltrexone / Q000031:analogs & derivatives*; D009292:Narcotic Antagonists / Q000494:pharmacology; D009842:Oligopeptides / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology*; D017465:Receptors, Opioid, delta
D007211:Indoles; D009019:Morphinans; D009292:Narcotic Antagonists; D009842:Oligopeptides; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; C060209:deltorphin II, Ala(2)-; D009270:Naloxone; D009271:Naltrexone; C055382:naltrindole