A relation between maze performance and increased ethanol intake in Long–Evans rats☆

Abstract 

In addition to the neurochemical and genetic basis of high ethanol consumption, there has been renewed interest in studying the role of behavioral variables and their relation to ethanol consumption. The present study was designed to assess whether a relation exists between a behavioral variable such as maze learning ability and ethanol consumption. Sixty, male, Long–Evans rats, exposed to food and water ad libitum, were given a daily trial in a complex, 16-arm T-maze for 19 consecutive days. The number of errors and time to complete the maze were monitored. Individual maze variable scores were transformed and then combined to allot each animal with an index of overall maze performance, with a smaller maze index score denoting good performance. After completion of maze testing, animals were given alternate-day, free-choice presentations of water and ascending doses of ethanol solutions (2%–10%), followed by a 10-day maintenance period with 10% ethanol. Animals were subsequently separated into two groups of high and low drinkers to examine any relation between differential ethanol intake and maze performance. A significant negative correlation between maze index and ethanol intake for the high drinkers group indicated that a smaller maze index was related to increased ethanol intake. No significant correlation was obtained for the low drinkers group. These results seem to indicate that individual variation in learning ability seems to be related to increased ethanol intake. Thus, innate learning processes may be a relevant trait when one attempts to understand the behaviors related to ethanol intake and preference.

Keywords:  Ethanol, Learning ability, Maze, Voluntary intake, Rat