SR 141716A enhances spatial memory as assessed in a radial-arm maze task in rats

A tonically active endogenous cannabinoid system has been proposed to modulate learning and memory. The purpose of the present study was to determine whether administration of the cannabinoid CB 1 receptor antagonist N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1 H-pyrazole-3-carboxamide HCl (SR 141716A) would enhance memory as assessed in an eight-arm radial maze task. Because the high degree of choice accuracy in the standard radial-arm maze procedure precludes the possibility of detecting memory enhancement, the difficulty of the task was increased by imposing a delay of varying durations between a two-phase procedure consisting of acquisition and test phases. Significantly fewer errors were committed during the test phase following an injection of SR 141716A than the vehicle treatment. These results provide additional evidence supporting the hypothesis that endogenous cannabinoid systems play a role in memory processes.