REWARDING AFFECTIVE PROPERTIES OF INTRA-NUCLEUS ACCUMBENS INJECTIONS OF TESTOSTERONE

On alternating days, adult male Long-Evans rats implanted with bilater al cannulas in the nucleus accumbens received intracerebral injections of testosterone in a water-soluble cyclodextrin inclusion complex (0. 125, 0.25, or 0.5 mu g/0.5 mu l saline) or saline immediately prior to being confined for 30 min to 1 of 2 compartments of a place-preferenc e apparatus. All rats received 8 days of pairings (4 hormone and 4 sal ine). On Day 9 the rats were given a 20-min test session during which they had access to all compartments of the apparatus. No hormone was i njected prior to the test session. On the test day, rats spent signifi cantly more time in the compartment previously paired with bilateral i ntra-accumbens injections of testosterone (0.25 and 0.5 mu g/0.5 mu l saline) than in the compartment previously paired with saline injectio ns. The findings indicate that intra-accumbens injections of testoster one are sufficient to produce reward.