TY - JOUR T1 - Corticosteroid Regulation of Ion Channel Conductances and mRNA Levels in Individual Hippocampal CA1 Neurons JF - The Journal of Neuroscience JO - J. Neurosci. SP - 2685 LP - 2696 DO - 10.1523/JNEUROSCI.18-07-02685.1998 VL - 18 IS - 7 AU - Suresh M. Nair AU - Taco R. Werkman AU - Johanna Craig AU - Richard Finnell AU - Marian Joƫls AU - James H. Eberwine Y1 - 1998/04/01 UR - http://www.jneurosci.org/content/18/7/2685.abstract N2 - Overexposure to corticosteroid hormones is harmful to hippocampal neuronal integrity, likely by perturbation of calcium homeostasis. To identify molecular mechanisms at the single-cell level, we characterized mRNA expression corresponding to voltage- and ligand-gated Ca channels in individual dissociated CA1 neurons in response to long-term corticosterone (CORT) exposure. Predominant mineralocorticoid receptor occupation (ADC-LO group) resulted in low levels of P/Q- and L-type Ca channel mRNAs, high levels of GluR-2 versus GluR-1, and a high ratio of NMDAR-2A to NMDAR-2B mRNA. Corresponding alterations in protein expression were consistent with the restriction of Ca influx. In contrast, additional glucocorticoid receptor occupation (ADC-HI group) altered the expression of these mRNAs in a manner consistent with enhanced Ca influx; interestingly, qualitatively similar alterations were seen in control ADX neurons. Electrophysiological data from the same neurons indicate that Ca current amplitudes also are modulated by CORT, although on a shorter time scale. Finally, principal components analysis (PCA) suggests that neuronal AMPA and NMDA receptor composition may be regulated by MR and GR activation in a complex manner. Therefore, our data implicate molecular events by which CORT may regulate Ca influx into CA1 hippocampal neurons. ER -