Neuroscience 2003 Abstract
| Presentation Number: | 361.17 |
|---|---|
| Abstract Title: | Spermine relieves proton inhibition of kainate-induced responses in pyramidal cells. |
| Authors: |
Buldakova, S. L.*1
; Skatchkov, S. N.
; Eaton, M. J.
; Veh, R. W.
; Burnashev, N.
; Reichenbach, A.
1Inst. Evol Physiol and Biochem, St Petersburg, Russian Federation |
| Primary Theme and Topics |
Synaptic Transmission and Excitability - Ligand Gated Ion Channels -- Glutamate receptors: Non-NMDA receptors |
| Session: |
361. Non-NMDA Receptors: Regulation Poster |
| Presentation Time: | Monday, November 10, 2003 8:00 AM-9:00 AM |
| Location: | Morial Convention Center - Hall F-I, Board # C92 |
| Keywords: | POLYAMINE, AMPA RECEPTOR, PATCH CLAMP, PH |
Spermine (SP4+) one of the polyamines (PAs) switches paired pulse depression to facilitation in CA1 hippocampus (Brain Res 689(1995)189). In neocortex, relief from intracellular PA block of Ca2+ permeable GluR2-lacking-AMPAR in interneurons (INTs) may induce facilitation (Nature 401(1999)594). Moreover, extracellular SP potentiates GluR2-rich-AMPAR in CA1 pyramidal cells (PCs) (SFN-2002 online 540.8) that in addition contain GluR6(R) receptors linked to inhibitory INTs (J Neurosci 19(1999)653). These receptors are potentiated by extracellular SP (J.Neurosci.23(2003)1179) that might be released into the neuronal network from astrocytes (Glia 19(1997)171), specifically during ischemia-like conditions (Physiol Res 48(1999)S67). Here we studied the effect of SP on kainate-induced responses in PCs at acid pH as a model of ischemia. Non-enzymatically isolated CA1 PCs from 9-25 day old rats were identified by their localization in s. pyramidale; by acid-sensitive ion channels (ASIC) currents; and by GluR1-2-4 immunolabel. We made whole cell recordings with SP-filled (0.2 mM) pipettes while applying acid and neutral kainate with and without SP. While responses to kainate were almost completely inhibited at pH 5.6 in PCs, the responses in INTs were growing as ASIC currents were activated. In INTs, external 50 µM SP or 10 µM IEM1460 (a synthetic amine adamantane) depressed kainate-induced inward currents at all pH, but in PCs SP relieved inhibition caused by acid pH, suggesting that SP and IEM1460 have extracellular binding sites and compete with H+.
Supported by NIH-MBRS-GM5-340508/09, NIH-RCMI G12RR03035, DFG Ve-187/1-3, DFG 849/3-2 and BMB+F (IDZL, 01KS 9504/C5)
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2003 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2003. Online.
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