Sub-acute insulin therapy does not affect long-term visiospatial learning and memory in mice assessed using Barnes maze

Abstract

Insulin is a common hypoglycaemic agent used to treat diabetes, but it has also been reported to exert other effects on the body including modulation cognition. Reported findings on insulin effect on learning and memory are scanty and often conflicting. This study was aimed at evaluating the effect of sub-acute insulin therapy on visio-spatial learning and memory using Barnes maze. Twelve young mice of both sexes, weighing between 20 – 22 g, were divided into control and insulin-treated groups (n = 6). They were administered subcutaneously with deionized water (control) or insulin (10 I.U./kg/day) for seven days. During the last three days of treatments, the mice were subjected to two-day training and one-day probe trial of Barnes maze. Number of primary head searches on day 2 was reduced compared to day 1 for both the insulin-treated (4.17 ± 0.8 s and 11.45 ± 1.9 s) and control (10.0 ± 3.2 s and 19.95 ± 4.5 s) groups (P < 0.05), but the values obtained in the two groups did not differ (P > 0.05). Similarly, there was no difference between the insulin-treated and control groups in latency to locate the escape hole, time spent and number of head searches per quadrant. It was concluded that sub-acute insulin therapy did not affect long-term visio-spatial learning and memory in mice.

Keywords: insulin, visio-spatial learning and memory, long-term memory, Barnes maze, mice