Effects of ethanol withdrawal on beta-endorphin levels in rat brain and pituitary.
Rats which received a liquid diet containing 6.5% (w/v) ethanol for three weeks became tolerant to the hypothermic effect of an acute dose of ethanol. Withdrawal of this diet was followed by loss of the tolerance within 3 days, and by an accompanying pattern of changes in levels of immunoreactive-ir-beta-endorphin in several brain regions. An initial decrease in levels on days 1 and 3 of withdrawal was followed by recovery to control levels on days 8 and 15. This pattern was found in the arcuate nucleus, amygdala, septum, periventricular thalamus and pre-optic periventricular hypothalamus (POPH), but was statistically significant only in the POPH. A different pattern of change in ir-beta-endorphin levels was found in the pituitary. The anterior lobe showed a significant depletion of ir-beta-endorphin levels before alcohol withdrawal, which recovered by day 8 of withdrawal. This depletion was probably not related to the loss of tolerance to ethanol but was a response to a perturbation of the hypothalamic-pituitary axis of hormonal control.
Hutchison
W D
WD
Department of Pharmacology, University of Toronto, Canada.
Gianoulakis
C
C
Kalant
H
H
D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001835:Body Weight; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D009928:Organ Specificity; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013375:Substance Withdrawal Syndrome; D001615:beta-Endorphin / Q000378:metabolism*
D000431:Ethanol; D001615:beta-Endorphin