Effects of naloxone, beta-endorphin and ACTH on acquisition of schedule-induced polydipsia.
A series of three experiments examined the possible involvement of endogenous opioid peptides in the development of schedule-induced polydipsia in rats. Repeated pretraining treatment with 2 mg/kg naloxone impaired acquisition of schedule-induced polydipsia, whereas the same treatment injected after training increased drinking. This later effect was time dependent, since a 30-min delay in the injection of naloxone resulted in a disappearance of its effect. Post-training injections of 10 micrograms/kg beta-endorphin or ACTH delayed the development of drinking. These findings are consistent with the hypothesis that endogenous opioid peptides modulate the development of schedule-induced polydipsia.
Tazi
A
A
Dantzer
R
R
Mormede
P
P
Le Moal
M
M
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D004327:Drinking Behavior / Q000187:drug effects; D004723:Endorphins / Q000494:pharmacology*; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012055:Reinforcement Schedule; D013894:Thirst / Q000187:drug effects*; D013997:Time Factors; D001615:beta-Endorphin
D004723:Endorphins; D009270:Naloxone; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone