Experience-dependent expression of rat hippocampal Arc and Homer 1a after spatial learning on 8-arm and 12-arm radial mazes

Abstract The expression of Arc and Homer 1a ( H1a ) depends on neural activity. This study was designed to determine hippocampal Arc and H1a mRNA expression levels after spatial learning with differing behavioral task demands. Forty-four male rats were distributed into 11 groups of four. One group received no training or trial sessions. Of the ten remaining groups, three were tested on the 8-arm maze, three on the 12-arm maze, two on the 8-arm maze and then the 12-arm maze, and two on the 12-arm maze and then the 8-arm maze. Each animal was sacrificed 30 min after the last session of maze testing and its hippocampus was immediately dissected and stored at −80 °C. The level of mRNA expression at different stages of maze learning was determined using real-time reverse-transcription polymerase chain reaction (qRT-PCR). Significantly elevated expression of both Arc and H1a was observed. The orchestrated expression levels of both genes were correlated with the behavioral task demand level and behavioral performance.