NEONATAL CAFFEINE ALTERS PASSIVE-AVOIDANCE RETENTION IN RATS IN AN AGE-RELATED AND GENDER-RELATED MANNER

Chronic administration of an adenosine receptor antagonist disturbs sp atial learning and memory in adult mice and neonatal caffeine exposure results in long-term behavioral and biochemical sequelae in mice and rats. We thus postulated that early treatment with caffeine would have latent effects on learning and memory as measured in a passive avoida nce paradigm. Rats were not handled or received caffeine (15-20 mg/kg/ day) by gavage over postnatal days 2-6. At 28 or 70-90 days of age, ra ts were trained to avoid an electrified grid and tested for retention 24 h, 72 h, and 7 days later. At 28 days, caffeine-exposed rats requir ed more trials to meet criterion than did control rats, regardless of gender. There was minimal effect on retention of either neonatal treat ment or gender at this age. At 70-90 days, there was no effect of eith er gender or treatment on learning; however, there was a significant e ffect of gender (P < 0.05) on retention at 24 h that was more pronounc ed in neonatally caffeine-treated rats (P < 0.01). At 72 h, the effect of caffeine on retention differed between male and female rats. Neona tal caffeine exposure significantly improved retention in females (P < 0.01) and significantly decreased retention in males (P < 0.05). Thus , caffeine exposure limited to the first week of life resulted in alte rations in passive avoidance retention that became apparent over puber tal development. These changes were a function of the gender of the an imal.