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Ethanol dependence in the rat: a parametric analysis.

Rats were maintained on liquid diets as their sole source of calories and fluid for 10, 15, 20, and 30 days. The diets consisted 35-40% of total calories in the form of ethanol. This procedure resulted in substantial ethanol intake leading to behavioral intoxication. Blood ethanol concentrations were found to be elevated throughout the day with a peak during the dark phase of the light cycle. The removal of ethanol resulted in evidence of physiological dependence, including behavioral manifestation of autonomic and somatic dysfunction and an increased susceptibility to audiogenic convulsions. Ten days of ethanol exposure was found to be sufficient for the reliable induction of ethanol dependence. Further increases in ethanol exposure resulted in increased hyperexcitability as measured by susceptibility to audiogenic convulsions. The severity of withdrawal behavior was found to be correlated with the blood ethanol concentration measured upon ethanol removal. A behavioral rating scale for the evaluation of alcohol withdrawal intensity in rats is described.

Animals↗

PubMedDate not supplied

The effect of age on ethanol metabolism and on the hypothermic and hypnotic responses to ethanol in the Fischer 344 rat.

The hypothesis that the central nervous system (CNS) of aged rats is more sensitive to acute ethanol effects was examined by measuring ethanol elimination rates, and the hypothermic and hypnotic responses to ethanol in four age groups (3, 12, 21, and 30 months) of Fischer 344 rats. Following a 2.5 g/kg intraperitoneal dose of ethanol, rectal temperature and blood ethanol concentration (BEC) were measured at regular intervals for 8 hr. The 30-month group's hypothermic response to ethanol was equivalent to the 3-month group's despite lower peak BEC. Response to a hypnotic dose (3.0 g/kg) of ethanol was evaluated by measuring the time for regain of righting reflex (RORR) and the BEC at RORR. The 3-month group slept for a shorter time, and awoke at a higher BEC, than the 12- or 21-month groups. The response of the 30-month group was more complex. Although this group had the lowest BEC at RORR, their sleep time was equivalent to the 3-month group. The shortened sleep time of the 30-month group is consistent with the observation of significantly lower peak BEC and higher metabolic rate (calculated from Widmark r values) in this group. Thus, aged rats of the Fischer 344 strain may be more sensitive to acute ethanol, but these CNS effects may be partially offset by enhanced ethanol disposition at older ages.

Aging↗