Fletcher BR, Guzowski JF, Baxter MG, Shapiro ML, Rapp PR (2004) Hippocampal Arc and Homer 1a expression in behaviorally characterized 192 IgG-saporin lesioned rats. Neuroscience 2004 Abstracts 436.4. Society for Neuroscience, San Diego, CA.
Summary: Fornix lesions impair hippocampal dependent learning and block behavioral induction of the immediate-early gene Arc. The present experiment tested the role of cholinergic innervation in the transcriptional induction of the activity related immediate-early genes Arc and Homer 1a. 192 IgG-saporin or vehicle was injected into the medial septal nucleus and vertical diagonal band. Behavioral characterization on cued and spatial delayed match-to-place tasks in a radial arm water maze revealed an impairment in cognitive flexibility, but not spatial memory in lesioned animals. Immediately after animals explored two novel environments their brains were processed for fluorescence in situ hybridization with probes for Arc and Homer 1a to reveal the recent activation history of individual neurons. Confocal stereological quantification of labeling in the CA1 and CA3 cell fields of the hippocampus revealed no dramatic difference in number of positive cells between groups. These results show that, unlike fornix lesions, cholinergic denervation of the hippocampus is not sufficient to block behavioral activation of Arc or Homer 1a transcription. Therefore, cholinergic innervation is not required for Arc or Homer 1a expression.
Related Products: 192-IgG-SAP (Cat. #IT-01)