An investigation of the role of neurotrophins in recognition memory in the rat

Abstract

Acquisition and consolidation of newly-acquired information is essential for formation of long-lasting memories, and both these processes may share common signaling pathways. The neurotrophins NGF, BDNF, NTS and NT4 have diverse functions in the adult brain, including learning and memory. Their biological effects are elicited by binding to Trk receptors and activation o f the ERK/MAPK pathway or the PI3K/AKT pathway which is believed to mediate protein synthesis, which has previously been identified as an essential process in memory formation (Kelly et al., 2003). In this study we investigated the roles of neurotrophins in both acquisition and consolidation of recognition memory by using neutralising antibodies against each neurotrophin isoform. An object recognition task was used to test acquisition and consolidation of memory; rats were tested 10min and 24hr after training to discriminate experimentally between acquisition and consolidation respectively. Rats treated with the pan-Trk antagonist tyrphostin AG879 were unable to discriminate between the novel and the familiar object at both 10min and 24hr when compared with controls, suggesting Trk receptor activation is required for both acquisition and consolidation, in contrast, rats treated with anti-BDNF, anti-NGF and anti-NT4/5 displayed comparable learning to control rats at the 10min timepoint, but displayed learning impairments 24hr later. Treatment with anti-NT3 had no effect on learning at either timepoint.