Intrahypothalamic injection of deltorphin-II alters body temperature in rats.
The present study investigated the effect of H-Try-d-Ala-Phe-Glu-Val-Gly-NH2 deltorphin-II, a selective delta-2 agonist, and [d-Pen(2),d-Pen(5)]enkephalin, a selective delta-1 agonist, on body temperature in the rat. Microinjected into the preoptic anterior hypothalamus (POAH), deltorphin-II (0.1-1 microg) produced an immediate dose-related hyperthermia following injection. Injection of the delta-2 antagonist naltriben into the preoptic anterior hypothalamus (1 microg, 30 min prior to deltorphin-II) significantly attenuated the deltorphin-II-induced hyperthermia. Microinjection of [d-Pen(2),d-Pen(5)]enkephalin into the POAH (0.1-3 microg) did not affect Tb. The data demonstrate that delta-2 receptors are involved in the mediation of Tb effects, and deltorphin-II exerts its action directly on thermosensitive cells of the preoptic anterior hypothalamus. Delta-1 opioid receptors do not appear to be involved in the control of body temperature.
Benamar
Khalid
K
Center for Substance Abuse Research and Department of Pharmacology, Temple University School of Medicine, 3400 N. Broad Street, Philadelphia, PA 19140, USA. kbenamar@temple.edu
Rawls
Scott M
SM
Geller
Ellen B
EB
Adler
Martin W
MW
D000818:Animals; D001831:Body Temperature / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D007031:Hypothalamus / Q000187:drug effects* / Q000502:physiology; D007276:Injections, Intraventricular; D008297:Male; D009842:Oligopeptides / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley
D009842:Oligopeptides; C060209:deltorphin II, Ala(2)-