Neuroscience 2000 Abstract
| Presentation Number: | 315.8 |
|---|---|
| Abstract Title: | Activity dependent regulation of NMDA receptor decay time in developing rodent superior colliculus. |
| Authors: |
Townsend, T. M.*1
; Shi, J.1
; Constantine-Paton, M.1
1Biology, Massachusetts Institute of Technology, Cambridge, MA |
| Primary Theme and Topics |
A. Development and Regeneration - 8. Formation and specificity of synapses |
| Secondary Theme and Topics | C. Excitable Membranes and Synaptic Transmission<br />- 33. Synaptic plasticity |
| Session: |
315. Formation and specificity of synapses IV Poster |
| Presentation Time: | Monday, November 6, 2000 4:00 PM-5:00 PM |
| Location: | Hall G-J |
| Keywords: | synapse, glutamate, plasticity, calcineurin |
Changes in the kinetics of the NMDA type glutamate receptor (NMDAR) have been implicated in synapse maturation in several brain regions including the superior colliculus (SC). While the evidence is compelling that the subunit composition of the NMDAR does regulate the kinetics of the NMDAR current decay during development, we have recently reported that 35-45% of the change in the NMDAR current occurs over a 24 hour period between postnatal day 10 (P10) and P11 in the rat SC. In that study (SFN'99) we concluded that activity of the protein phosphatase 2B (calcineurin) could account for this rapid alteration of the current decay. Here we demonstrate that this abrupt change in the NMDA receptor function is activity dependent. Stimulation of the optic tract for one hour on P10 induces a precocious abbreviation of the NMDAR current decay, and is reversed by inhibition of calcineurin (CaN). In contrast silencing activity in SC slices on P11 for 3 hours with TTX lengthens the NMDAR decay time. Stimulation on P10 was ineffective in shortening the NMDAR current decay in the presence of APV or if the SC neuron was voltage clamped during stimulation indicating that NMDAR function was necessary. Therefore, we suggest that CaN is part of a feedback cascade in which increased NMDAR activity shortens the fall time of the NMDAR current during development. This process appears distinct from CaN induced desensitization of the NMDAR because of the prolonged activity of CaN. The onset of the CaN effect on the NMDAR is coincident with, and therefore may be involved in, the refinement of the retino-collicular projection.
Supported by NIH grant NS32290 (MCP, JS), NIDA DA 07290-03S1 (MT)
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2000 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2000. Online.
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