ALLOPREGNANOLONE HAS MNEMONIC-ENHANCING EFFECTS IN FEMALE RATS.

ESCUDERO C.; CERIONI S.; GARC¨ªA S.; YUNES R.; CABRERA R.

Rosario

Congreso; XLI REUNION ANUAL DE LA SOCIEDAD ARGENTINA DE FARMACOLOGÍA EXPERIMENTAL; 2009

SAFE

Learning and memory processes may be influenced by fluctuations in steroid hormones and neurosteriods, such as Allopregnanolone (Allo). In this study, we investigated the effects of the subcutaneous administration of estrogen (E) and progesterone (P) to ovariectomized (OVX) rats, infused in CA1-CA3 hippocampus regions with Allo (6ìM) or vehicle (30min before training), on the inhibitory avoidance task (Step Down, SD). All groups were trained in SD task and, after 24-h intertrial delay, SD latency was tested. The results were analized vs vehicle by t-test (p<0.05 was significant). No differences were observed in SD latencies when OVX rats received hippocampal administration (HA) of Allo. The administration of estradiol (E) (0,1mg/kg, 48h before training), did not modify the SD latency after HA of Allo, but in E-P primed group (0,1mg/kg and 4mg/kg, 48hs and 5hs before training, respectively) Allo increased SD latencies. HA of bicuculine (GABAA antagonist) prior to Allo had not effect on the increased SD latencies observed in E-P group. The HA of AP-7 (NMDAreceptor-antagonist), (2ìg/ìl, 60min before training) prior to Allo in E-P rats reversed the increase of SD latencies observed before. Together, these data suggest that Allo would have positive mnemonic effects in the SD task in E-P primed rats and might act through the glutamatergic system. A antagonist) prior to Allo had not effect on the increased SD latencies observed in E-P group. The HA of AP-7 (NMDAreceptor-antagonist), (2ìg/ìl, 60min before training) prior to Allo in E-P rats reversed the increase of SD latencies observed before. Together, these data suggest that Allo would have positive mnemonic effects in the SD task in E-P primed rats and might act through the glutamatergic system.