Neuroscience 2002 Abstract
| Presentation Number: | 713.7 |
|---|---|
| Abstract Title: | AMPA CHANNEL DENSITY AND PROPERTIES CHANGE FOLLOWING CA/CAM TREATMENT IN CA1 PYRAMIDAL NEURONS. |
| Authors: |
Andrasfalvy, B. K.*1
; Magee, J. C.1
1 Neurosci Ctr, LSUHSC, New Orleans, LA |
| Primary Theme and Topics |
Synaptic Transmission and Excitability - Synaptic Plasticity -- Long-term potentiation (LTP) |
| Secondary Theme and Topics | Synaptic Transmission and Excitability<br />- Ligand Gated Ion Channels<br />-- Glutamate receptors: Non-NMDA receptors |
| Session: |
713. Synaptic plasticity: long-term potentiation IX Slide |
| Presentation Time: | Wednesday, November 6, 2002 2:30 PM-2:45 PM |
| Location: | Room 203A |
| Keywords: | hippocampus, Ca/CaM, plasticity, phosphorylation |
LTP is thought to be initiated by a transient activation of NMDA receptors causing an increase of [Ca2+]i in the cell. It has been reported that intracellular application of high Ca/CaM could mimic LTP without any electric stimulation. We investigated whether this application could cause the same kind of postsynaptic modifications of AMPA receptors as was seen with tetanus (see Andrasfalvy et al. SFN abstract 2001). The number of AMPA receptors, single-channel conductance, open probability and channel kinetics were examined after 5 min Ca/CaM treatment through the patch-pipette. We excised an outside-out patch from the dendrite and rapidly applied glutamate (10mM) and performed a non-stationary fluctuation analysis. We compared our result with other outside-out patches excised from electrically potentiated cells. Thus far the Ca/CaM application has produced the same type of changes in AMPA receptor properties as was seen following electric stimulation. The channel number was increased (N=3268 ± 454 vs 1726 ± 120) but the maximum open-probability (Po,max=0.91 ± 0.02 vs 0.87 ± 0.03), and the single channel conductance (γ =7.65 ± 0.95 vs 9.05 ± 0.87 pS) did not change significantly compared with control. The deactivation and desensitization time constants of AMPA currents were slightly increased. In all cases I-V curves, glutamate affinity and rectification index were similar to control. With 1μM AIP (Cam-KII inhibitor) the effect was diminished. When Ca/CaM were applied in the soma and the patch was excised from soma, there was no change detected. These results suggest that phosphorylation regulated AMPA receptor insertion might be a key element in synaptic plasticity.
Supported by NS39458
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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