The present study tested the effects of in vivo administration of brain-derived neurotrophic factor (BDNF) and of its antibody (anti-BDNF) in a Morris Water Maze (MWM) task. Adult male rats were trained for three days in a MWM. At the end of the last training trial, subjects were injected intracerebroventricularly with one of the following: (i) BDNF (24 microg); (ii) anti-BDNF (25 microg); or (iii) vehicle (PBS, injection volume 10 microl). On day 5, subjects were tested for memory retention, pain sensitivity and locomotor behaviour. No differences emerged in the MWM as a function of treatment, even with a reduced number of acquisition trials. Nonetheless, BDNF affected both pain threshold in the hot-plate test, as well as exploratory behaviour in the open field test.