Spatial working memory in rats: the effect of the dipeptide gamma-L-glutamyl-taurine and haloperidol.

To assess the possible involvement of the dipeptide gamma-L-glutamyl-taurine (Litoralon) and some of its analogues in the maintenance of spatial working memory, rats were treated with the dipeptides immediately or 2 hours after completing the first four choices in an 8 arm radial maze, or 3 hours before the test to exclude proactive effects of the compounds. Treatment with Litoralon, SZJ 3381 and 3361 at doses of 100 and 500 micrograms/kg (i.p.) did not impair spatial memory in rats, regardless of when these substances were injected during the session. By contrast, haloperidol (500 micrograms/kg, i.p.) treatment resulted in a dramatic decrease of performance.