Corticosterone targets distinct steps of synaptic transmission via concentration specific activation of mineralocorticoid and glucocorticoid receptors
Article first published online: 28 OCT 2013
© 2013 International Society for Neurochemistry
Journal of Neurochemistry
Volume 128, Issue 4, pages 476–490, February 2014
How to Cite
J. Neurochem. (2014) 128, 476–490.
- Issue published online: 9 FEB 2014
- Article first published online: 28 OCT 2013
- Accepted manuscript online: 4 OCT 2013 01:28AM EST
- Manuscript Accepted: 30 SEP 2013
- Manuscript Revised: 15 SEP 2013
- Manuscript Received: 4 JUL 2013
- IISRO-IISc STC. Grant Number: ISTC-255
- Department of Science and Technology, Centre for Mathematical Biology. Grant Number: SR/S4/MS 419/07
- glucocorticoid receptor;
- mEPSC ;
- mineralocorticoid receptor;
Hippocampal neurons are affected by chronic stress and have a high density of cytoplasmic mineralocorticoid and glucocorticoid receptors (MR and GR). Detailed studies on the genomic effects of the stress hormone corticosterone at physiologically relevant concentrations on different steps in synaptic transmission are limited. In this study, we tried to delineate how activation of MR and GR by different concentrations of corticosterone affects synaptic transmission at various levels. The effect of 3-h corticosterone (25, 50, and 100 nM) treatment on depolarization-mediated calcium influx, vesicular release and properties of miniature excitatory post-synaptic currents (mEPSCs) were studied in cultured hippocampal neurons. Activation of MR with 25 nM corticosterone treatment resulted in enhanced depolarization-mediated calcium influx via a transcription-dependent process and increased frequency of mEPSCs with larger amplitude. On the other hand, activation of GR upon 100 nM corticosterone treatment resulted in increase in the rate of vesicular release via the genomic actions of GR. Furthermore, GR activation led to significant increase in the frequency of mEPSCs with larger amplitude and faster decay. Our studies indicate that differential activation of the dual receptor system of MR and GR by corticosterone targets the steps in synaptic transmission differently.
The stress hormone corticosterone has multiple effects on neuronal physiology and function. In this study we show corticosterone differentially targets the steps of synaptic transmission depending on the genomic effects of its cognate receptors namely mineralocorticoid and glucocorticoid receptors (MR and GR), within its physiological range. Increasing concentrations of corticosterone enhanced synaptic transmission at distinct levels.