COMPARISION OF EFFECTS OF CARVEDILOL AND PROPRANOLOL ON LEARNING AND MEMORY IN RATS

Alzheimer’s disease is one of the commonest neurodegenerative disorders encountered worldwide. Rise in oxygen free radical levels is considered to be the main reason for the signs and symptoms of Alzheimer’s disease. Carvedilol, due to its antioxidant property, has been shown to have neuroprotective action. The objective of this study was to investigate the effect of Carvedilol against scopolamine induced cognitive impairment and compare its effect with that of propranolol. Wistar rats (150-200 g) were divided into 6 groups (n=6 each). Control group and scopolamine only group received equivolume of water for 15days. Each of the four drug treated groups received either Carvedilol 5mg/kg or Propranolol 25mg/kg for 15 days. . Scopolamine 0.5 mg/kg was administered i.p. 5 min before the learning trial in two of the groups of rats treated with carvedilol and propranolol and to the scopolamine control group of rats. Passive avoidance test using two compartment model was used to test learning and memory in the animals. Amongst the scopolamine treated groups, time taken to enter the dark compartment was higher in both the propranolol group (79 ± 5 secs) as well as the carvedilol group (142.33 ±7.5 secs) as compared to the control group (33.98 ± 4 secs). Time spent in dark compartment was much lesser in Carvedilol group (38.83 ± 2.24 secs) and Propranolol group (75.83 ± 6.30 secs) as compared to control group (121.83 ± 10.87 secs). All the differences in time were statistically significant. Therefore, in conclusion carvedilol seems to have a positive effect on learning and memory in scopolamine induced amnesia in rats.