BEHAVIORALLY INDUCED EXPRESSION OF NEUROPEPTIDE Y AND ARC IN YOUNG AND AGED RODENTS

D.F. Marrone¹*; M.K. Chawla¹; M.R. Penner¹; M.J. Schaener¹; A. Lanahan²; P.F. Worley²; C.A. Barnes¹

1. NSMA , Univ Arizona, Tucson, AZ, USA
2. Neurosci & Neurol, Johns Hopkins Univ, Baltimore, MD, USA

Neuronal activity induces a hierarchical program of mRNA transcription that involves both immediate early (IEG) and delayed early genes (DERG) that are hypothesized to underlie learning-dependent neuronal plasticity (Lanahan & Worley, 1998). IEGs are transcribed within minutes of a novel learning experience, as can be visualized by the technique known as cellular compartment analysis of temporal activity by fluorescence in situ hybridization (catFISH). Despite the wealth of data generated on IEG expression, relatively little is known about DERGs. This class of genes shows stimulus-dependent transcriptional induction similar to IEGs; however, an initial wave of transcription and de novo protein synthesis is necessary in order for the DERGs to be transcribed (Goelet et al., 1986). DERGs are implicated in mediating long-term changes in cell function in many non-neuronal systems. Thus, these gene products are a prime candidate for mediating long-term functional changes associated with learning and memory. Despite these functional implications, the temporal dynamics and cellular specificity of DERG expression remains to be clarified. Towards such an understanding, we have focused on a candidate DERG, Neuropeptide Y (NPY), which is transcribed in a behavior-dependent and cell-specific manner similar to IEGs; although the spatio-temporal dynamics of NPY transcription appear to be unique. In addition, we are currently characterizing the degree to which behaviorally-induced NPY is co-localized with the IEG Arc, as well as the effects of aging on these transcription dynamics.

Support Contributed By: AG009219, NSERC PDF-301315-2004

Key words: plasticity, gene expression, hippocampus, Arc