Alcohol tolerance in rats submitted to different periods of chronic and acute ethanol intake / Tolerancia al alcohol en ratas sometidas a diferentes períodos de consumo agudo y crónico de etanol

The development of tolerance to the effects of ethanol is not uniform and may vary according to the actual and previous pattern of consumption. In this experiment we assessed body temperature and the recovery of two reflexes after a high dose of ethanol in rats submitted to chronic and acute ethanol consumption. Animals were previously submitted to chronic or acute alcohol consumption from postnatal day 21 until postnatal days 56 and 84. On the testing days, the animals received a single dose of 25% ethanol (5 g/kg, i.p.) or the same amount of saline solution. The results showed that animals were affected in the day 56 to a greater extent than in the day 84 by chronic heavy consumption of ethanol solution. With moderate and acute ethanol consumption, the 56-day-old animals developed greater tolerance. However, tolerance was not developed for the motor-impairing effects, since all groups required a long time to recover reflexes (AU)

El desarrollo de tolerancia a los efectos del alcohol no es uniforme, y suele variar según el patrón de consumo previo y actual. En este trabajo se evaluó la temperatura corporal y el tiempo de recuperación de dos reflejos tras el consumo crónico y agudo de elevadas dosis de etanol. Previamente, los animales bebieron alcohol de forma crónica o aguda desde los 21 hasta los 56 y 84 días de edad. Durante los días de evaluación, los animales recibieron una única dosis de etanol al 25% (5 g/kg, i.p.), o la misma cantidad de solución salina. Los resultados mostraron una mayor afectación a los 56 días de consumo crónico elevado de etanol respecto a los 84 días. Con un consumo moderado o agudo de etanol, los animales de 56 días desarrollaron una mayor tolerancia. Sin embargo, esta tolerancia no se observó en cuanto a los déficits motores, dado que todos los grupos necesitaron un largo período de tiempo para recuperar los reflejos (AU)

Chronic ethanol intake and object recognition in young and adult rats.

Alcoholism is one of the most important problems today. Chronic alcohol intake produces many cognitive deficits in humans, especially in memory. To evaluate the memory deficits in alcoholism it is very common to use animal models. In the present work, rats receiving chronic alcohol intake and not submitted to withdrawal were evaluated in a spontaneous delayed nonmatching-to-sample test (EDNMS). Ninety-six male Wistar rats, 90 and 180 days old, were used in the experiment. Alcohol-treated rats (ALCY and ALCA) had free access to an aqueous ethanol solution as the only available liquid source from 21 days of age to the end of experiment for both groups (90 and 180 days). Animals were then evaluated in a nonspatial memory test based on the paradigm EDNMS using delays of 1, 15, and 60 min. The results show that chronic alcohol intake impairs the rats' performance, both at 90 and 180 days old, in this test of object recognition when the delay interval is of 1 h. Chronic alcohol intake with no withdrawal periods produces memory deficits and these effects of alcohol begin in the early period of intake. Moreover, we may state that the paradigm of EDNMS with a delay interval of 60 min is useful to evaluate several cognitive deficits such as hippocampal-derived memory impairment.