Absence of acute tolerance to ethanol hypnosis in F-344 and BN/BIRIJ rats.
Male Fischer 344 (F-344) rats of three different ages (4, 13, and 25 months) and male Brown Norway (BN/BIRIJ) rats (4 months) were injected (IP) with a hypnotic dose of ethanol (3.0 g/kg, 10% w/v in saline). Half of the animals were decapitated and brains extracted immediately upon loss of the righting reflex (LRR), while the other half were allowed to reach recovery of the righting reflex (RRR), at which time brains were extracted. Brain alcohol analyses revealed significantly higher concentrations in young F-344 rats at both LRR and RRR, indicating less sensitivity of target tissue to ethanol hypnosis in the young of that strain. All age groups of the F-344 rats as well as the young BN/BIRIJ rats displayed lower brain concentrations of ethanol at RRR than at LRR, a finding opposite to that characteristic of acute tolerance. The relationship of LRR to RRR values did not differ among the age groups of F-344 rats. We conclude that the F-344 and BN/BIRIJ strains do not develop acute tolerance to ethanol hypnosis. The findings are consistent with the hypothesis that animals with low ethanol preferences, such as the F-344 and BN/BIRIJ strains, also have low capabilities to develop acute tolerance to ethanol hypnosis.
York
J L
JL
Research Institute on Addictions, Buffalo, NY 14203.
Chan
A W
AW
D000375:Aging / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000378:metabolism; D004361:Drug Tolerance; D000431:Ethanol / Q000008:administration & dosage / Q000378:metabolism; D006990:Hypnosis; D008297:Male; D051381:Rats; D011914:Rats, Inbred BN; D011916:Rats, Inbred F344; D012018:Reflex
D000431:Ethanol