Studies on the Acquisition of Behavioral Tolerance to Alcohol

Abstract

An attempt was made to replicate a study by Troshina which purported to demonstrate an acquired physiological tolerance to alcohol. The results of the attempted replication were in essential disagreement with Troshina''s findings, and gave no indication of the development of tolerance to alcohol. A 2nd experiment was performed to investigate the problem using a method designed to overcome the shortcomings of the earlier studies. Seven male Sprague-Dawley rats were given alcohol injections 3 times a week for 30 weeks. A similar control group was given comparable quantities of water. After 30 weeks treatment was discontinued and all the animals were trained to asymptote on an escape task, the animals being required to rise on their hind legs and pull a chain to terminate electrical shock. Escape latencies were then measured before and after an injection of alcohol. The results showed that the animals which had previously been treated with alcohol manifested no difference between their pre- and postalcohol performance. In contrast, the group previously treated with water showed a large initial significant increase in both mean and variability of the postalcohol escape latencies. This early deficit in the performance of the control group under alcohol rapidly declined, so that at the end of 20 postalcohol trials the animals were performing at their pre-alcohol level. These results were interpreted to indicate (a) the presence, in the experimental group, of a tolerance to the effects of alcohol which was due to the earlier prolonged treatment with that drug; and (b) the rapid development in the control group of behavior which compensated for the initial deficit caused by the alcohol injection.