SR141716A, a cannabinoid CB1 receptor antagonist, improves memory in a delayed radial maze task.

An endogenous cannabinoid system may play an important role in controlling memory processes. SR141716A (N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamidehydrochloride), a selective cannabinoid CB(1) receptor antagonist, was studied in an eight-arm radial maze task in which either deficits or improvements in memory could be detected. This task required well-trained rats to recall after either a relatively short (3 h) or long (7 h) delay period where they had received rewards during an information phase in order to obtain the remaining rewards during a retention phase. SR141716A was administered intraperitoneally immediately after the information phase in order to determine the drug's effects on memory consolidation. Although SR141716A had no effect on the number of errors committed after a short interval, SR141716A significantly reduced the number of errors that occurred after 7 h. These results suggest that a cannabinoid CB(1) receptor antagonist can improve consolidation processes and thus may be useful in treating memory disorders.