Delayed ethanol effects on physiological and behavioral indices in the rat.
The purpose of this project was to examine time-dependent initial and delayed behavioral and physiological effects of acute and chronic ethanol administration in rats. Experiment 1 compared the 24-h changes in temperature (rectal probe), activity (open field), and analgesia (tail-flick test) induced by an acute 4-g/kg dose of ethanol before and after a chronic regimen of ethanol. Initial hypothermic, hypoactivity, and analgesic effects were found, but no delayed secondary effects were evident and tolerance occurred only for the analgesic measure. Experiment 2 examined dose-dependent, 48-h changes in temperature and activity (monitored simultaneously and continuously via implanted telemetry sensors) before and after a daily regimen of ethanol injections. Acute ethanol produced dose-dependent initial hypothermic and hypoactivity effects followed by a delayed hyperthermic effect. Following the chronic ethanol regimen, tolerance to all effects was evident. The results were discussed in terms of methodological differences in the two experiments and the possible basis for the delayed ethanol effects. There is a strong suggestion that the secondary hyperthermic effect represents not a rebound, homeostatic phenomenon restricted to the temperature system, but rather an "artifact" due to a disruption of the circadian rhythm, resulting in an absence of the normal reduction in activity seen during the light cycle.
Holloway
F A
FA
University of Oklahoma Health Sciences Center, Department of Psychiatry and Behavioral Sciences, Oklahoma City 73190-3000.
Miller
J M
JM
King
D A
DA
Bedingfield
J B
JB
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001831:Body Temperature / Q000187:drug effects*; D002940:Circadian Rhythm; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D000700:Analgesics; D000431:Ethanol