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.
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
Khalid
K
Benamar
Scott M
SM
Rawls
Ellen B
EB
Geller
Martin W
MW
Adler
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)-