Evaluation of Vigilance Promoting Drugs Modafinil and Caffeine on Cognition Enhancing Activities in Wistar Albino Rats-A Comparative Study

Abstract

Learning process can’t be made simple unless one is wakeful/attentive/aware of present situations. Worldwide, it is known fact that behavioral modulating actions of Caffeine is used in many common beverages, likewise modafinil appears to promote a possible facilitatory effect on cognitive function perhaps that is the primary reason why is it is been used in narcolepsy, obstructive sleep apnea, shiftwork and Jet lag syndrome. The rationale for conducting this animal experiment was to exploit/evaluate the vigilance promoting pharmacological actions of modafinil and compare with caffeine and rivastigmine. It promising agent for various indications like cognitive dysfunctional disorders, chronic alcoholism, attention-deficit hyperactivity disorder and schizophrenia. Two drugs modafinil 75mg/kg and caffeine 10mg/kg were used as test drugs and rivastigmine 5mg/kg as standard cognition enhancing and scopolamine 0.5mg/kg to induce amnesia in Wistar albino rats. Three different experimental models were used to screen the memory enhancing activities. The ability of the rats to retain chronic and working memory were screened by standard experiments like T-Maze and passive avoidance respectively. Morris water and T-Maze were used to test navigation and spatial task memory enhancing activities respectively. Total 72 rats were used in the study, 4 groups in each model, and 6 rats in each group. The obtained data were denoted as mean values and statistically analyzed by One-way ANOVA using SPSS 20.0 software. Both the test drugs and rivastigmine treated rats exhibited significant anti- amnesic activities among all three models compared to control (P<0.05). In passive avoidance, rivastigmine ranked maximum in memory retention abilities (17.83), whereas in modafinil treated rats showed similar results however; the rank of increased latency time (15.33 s) was not comparable with caffeine (13.17 s). In T-maze, the no. of mean correct spontaneous and rewarded alternations exhibited by caffeine and modafinil treated rats were 16.50±0.50 and 15.83±0.60 respectively and were comparable to the rivastigmine treated rats. In Morris water maze test, all three drugs caffeine, modafinil and rivastigmine treated group showed significant difference compared to the control. However, caffeine treated rats exhibited statistically significant (P<0.01) least escape latency time at probe trial compared to other groups and rats treated with modafinil showed maximum time in the probe quadrant by 27.37 s. The total amount of time spent in the probe quadrant and escape latency in caffeine and modafinil treated rats were comparable to rivastigmine treated rats.