Effects of morphine on plasma B-endorphin and cortisol levels and on body temperature in guinea-pigs pretreated with 6-hydroxydopamine.
1. i.c.v. morphine administration (50 micrograms/10 microliters) to sham-lesioned guinea-pigs produces a decrease of body temperature 90 min after injections. 2. This effect was blocked in animals that received i.c.v. 6-OHDA injections 20 days before. 3. On the other hand, morphine injection to sham-lesioned guinea-pigs resulted 30 and 90 min later in suppressed plasma B-END and cortisol concentration. 4. This suppressive effect was increased 20 days after 6-OHDA injections. 5. These results indicate that in the guinea-pig the effects of morphine on both body temperature and plasma levels of B-END and cortisol are altered by hypothalamic DA lesions, and suggest that hypothalamic DA neurons would be one of the sites participating in morphine-induced delayed decreased in plasma B-END and cortisol.
Milanés
M V
MV
Department of Physiology and Pharmacology, University School of Medicine, Murcia, Spain.
del Rio-García
J
J
Cremades
A
A
Fuente
T
T
D000818:Animals; D001831:Body Temperature / Q000187:drug effects*; D004298:Dopamine / Q000502:physiology; D005260:Female; D006168:Guinea Pigs; D006854:Hydrocortisone / Q000097:blood*; D006892:Hydroxydopamines / Q000494:pharmacology; D007031:Hypothalamus / Q000502:physiology; D007276:Injections, Intraventricular; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D016627:Oxidopamine; D011863:Radioimmunoassay; D001615:beta-Endorphin / Q000097:blood*
D006892:Hydroxydopamines; D001615:beta-Endorphin; D009020:Morphine; D016627:Oxidopamine; D004298:Dopamine; D006854:Hydrocortisone