The Effect of Ethanol and Hypoglycemia on Rat Performance in the Radial Arm Maze

Both hypoglycemia (HG) and ethanol (ETH) intoxication can cause serious impairment in physiological and psychological functioning. Their combination could cause more severe cognitive impairment than either condition alone. This experiment investigated the effects of hypoglycemia, ethanol intoxication, and their combination on rat radial arm maze performance. Eleven male rats were trained to a stable, low error rate performance in achieving food rewards in an eight arm radial arm-maze. Rats were then given either insulin (2 units/kg) or saline in combination with ETH doses of 250, 500, 1000, or 1500 mg/kg 20 minutes prior to the maze run. Treatment order was counterbalanced. Insulin significantly reduced blood glucose (BG) level. HG rats had a mean blood glucose (BG) level of 39.85 mg/dl, whereas non-HG rats had a mean BG level of 59.47 mg/dl. ETH did not affect BG. HG increased maze running time and decreased the total number of arm choice errors. ETH did not affect maze running time or choice accuracy. The combination of HG and ETH also did not affect choice accuracy. These results indicate that under these conditions, HG slows locomotion, but does not impair working memory as measured by maze performance errors. When administered to HG rats, ETH also does not further increase running time or the number of maze errors. These results indicate that, for the relatively short time required to complete the maze, the rats were able to overcome some drug effects in order to obtain food rewards.