Abstract

The hippocampus has an essential role in learning and memory and is a target for androgen actions. Thus, the effect of testosterone and its metabolites on learning and memory has attracted researchers' attention. The present study aimed to identify the effects of four-day bilateral intra-hippocampal infusion of nicotine and o-Acetyl L-carnitine alone and in combination on testosterone enanthate (TE)induced spatial learning deficits using Morris water maze (MWM). The expression of CREB, pCREB and BDNF proteins was quantified using western blots. We observed that bilateral intra-hippocampal infusion of TE significantly impaired spatial learning and a significant decrease in CREB, pCREB and BDNF protein markers compared to a control group that did not receive TE. In addition, administration of O-acetyl L-carnitine and/or nicotine reversed TE-induced spatial learning impairment in behavioural and molecular assessments. Thus, our findings suggest that administration of TE in the hippocampus of adult male rats impairs memory function, possibly via down-regulation of cAMP/PKA-CREB-BDNF signaling pathway.