Neuroscience 2001 Abstract
| Presentation Number: | 558.3 |
|---|---|
| Abstract Title: | SELECTIVE MAINTENANCE OF NMDA RECEPTOR FUNCTION IN DENTATE GRANULE CELLS DURING THE LATENT PERIOD OF TEMPORAL LOBE EPILEPSY. |
| Authors: |
Hsu, F. C.*1
; Rikhter, T. Y.1
; Ahmed, H.1
; Coulter, D. A.1,2
1Pediatric/Neurology, Children's Hosp Philadelphia, Philadelphia, PA 2Neuroscience Program, University of Pennsylvania, School of Medicine , Philadelphia, PA |
| Primary Theme and Topics |
Neurological and Psychiatric Conditions - Epilepsy -- Basic mechanisms |
| Secondary Theme and Topics | Synaptic Transmission and Excitability<br />- Ligand Gated Ion Channels<br />-- GABAa receptors |
| Session: |
558. Epilepsy: basic mechanisms--epileptogenesis II Poster |
| Presentation Time: | Tuesday, November 13, 2001 10:00 AM-11:00 AM |
| Location: | Exhibit Hall ZZ-47 |
| Keywords: | GABA RECEPTOR, PATCH CLAMP, KAINIC ACID, EXCITABILITY |
Epilepsy-associated alterations in GABA-A receptor subunit mRNA expression and function have been demonstrated in rat dentate granule cells (DGCs)(Brooks-Kayal et al., Nat. Med., 4(10) 1998; Rikhter et al., SFN Abstr. 1999). To further investigate the function of inhibitory and excitatory receptors in the latent period prior to the development of temporal lobe epilepsy, GABA-A, NMDA and non-NMDA receptor-mediated currents were examined in acutely isolated DGCs using whole cell patch clamp techniques. The amplitude of GABA-A and non-NMDA receptor-mediated currents were both significantly decreased in the DGCs of rats one week post pilocarpine-induced SE. The capacitance normalized current densities in response to application of GABA (1 mM) or kainate (1 mM along with 100 μM cyclothiazide) were decreased 48.2% {from 220.8 ± 17.0 (pA/pF; n = 39) to 114.3 ± 21.8 (pA/pF; n =32); mean ± SEM} and 45.2% {from 108.1 ± 10.1 (pA/pF; n =40) to 59.2 ± 11.1 (pA/pF; n =31)} respectively. In contrast, NMDA (100 μM along with 10 μM glycine in Mg-free solution)-evoked current density increased 11.9% {from 38.5 ± 4.3 (pA/pF; n =40) to 43.1 ± 7.5 (pA/pF; n =27)}. This selective maintenance of NMDA-evoked responses while other receptors are down-regulated should transiently enhance excitability in the dentate gyrus. This could play a crucial role in the subsequent development of temporal lobe epilepsy.
Supported by NIH-NINDS Grants NS-32403 and 38572 to DAC
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2001 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2001. Online.
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