JN Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Neurophysiol 77: 702-708, 1997;
0022-3077/97 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Jardemark, K.
Right arrow Articles by Jacobson, I.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Jardemark, K.
Right arrow Articles by Jacobson, I.

The Journal of Neurophysiology Vol. 77 No. 2 February 1997, pp. 702-708
Copyright ©1997 The American Physiological Society

Ca2+ Ion Permeability Properties of (R,S)alpha -Amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) Receptors in Isolated Interneurons From the Olfactory Bulb of the Rat

Kent Jardemark, Michael Nilsson, Håkan Muyderman, and Ingemar Jacobson

Department of Anatomy and Cellbiology, University of Göteborg, 413 90 Göteborg, Sweden

Jardemark, Kent, Michael Nilsson, Håkan Muyderman, and Ingemar Jacobson. Ca2+ ion permeability properties of (R,S)alpha -amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors in isolated interneurons from the olfactory bulb of the rat. J. Neurophysiol. 77: 702-708, 1997. The aim of the study was to investigate the divalent cation permeability of native alpha -amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) receptors expressed in interneurons of the olfactory bulb. Kainic acid (KA) was used as agonist to activate AMPA-receptor-mediated currents, which were recorded with the use of the patch-clamp technique. In interneurons acutely isolated from the olfactory bulb, the current responses to KA showed linear/outwardly rectifying current-voltage (I-V) relationships with a positive average reversal potential of +7 mV in normal external medium (1 mM Ca2+, 1 mM Mg2+). Raising the external Ca2+ concentration to 10 mM suppressed the amplitude, whereas omission of Ca2+ enhanced the amplitude of the current. Spectral analysis of the increase in current variance produced by KA indicated that the decreased amplitude observed in 10 mM Ca2+ was accompanied by a reduction in the apparent single-channel conductance. Raising the concentration of Mg2+ from 1 to 10 mM had a weak depressant effect on the KA-evoked current amplitude. No shift in the reversal potential was observed when the concentration of Ca2+ or Mg2+ was changed from 1 to 10 mM. Increasing the external medium concentration of Ca2+ to 60 mM not only further depressed the amplitudes of the KA-evoked currents but also gave a pronounced leftward shift in the average reversal potential to -32 ± 9 (SE) mV (N = 7). For neurons in primary culture, current responses to KA also showed linear/outwardly rectifying I-V relationships with a positive average reversal potential in normal external medium. Substituting N-methylglucamine for Na+ and increasing the Ca2+ concentration to 10 mM gave a leftward shift in the average reversal potential from +9 ± 3 mV to -47 ± 4 mV (N = 11) and caused a marked reduction in the amplitude of the KA-evoked currents at negative potentials. The permeability properties of the studied AMPA receptors were well predicted by the Eyring rate model (symmetrical, 2 barriers, 1 site). The model gave a pCa2+/pK+ permeability ratio of 0.06 for acutely isolated interneurons and 0.14 for interneurons in primary culture. The constant field theory, which failed to successfully reproduce all the experimental data, gave corresponding low permeability ratios of 0.18 and 0.40 for acutely isolated cells and cells in primary culture, respectively. Thus it is concluded that interneurons in the olfactory bulb mainly express AMPA receptors with low permeability to Ca2+ ions.




This article has been cited by other articles:


Home page
 Am. J. Physiol. Cell Physiol.Home page
L. J. Blakemore, M. Resasco, M. A. Mercado, and P. Q. Trombley
Evidence for Ca2+-permeable AMPA receptors in the olfactory bulb
Am J Physiol Cell Physiol, March 1, 2006; 290(3): C925 - C935.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
V. Egger, K. Svoboda, and Z. F. Mainen
Dendrodendritic Synaptic Signals in Olfactory Bulb Granule Cells: Local Spine Boost and Global Low-Threshold Spike
J. Neurosci., April 6, 2005; 25(14): 3521 - 3530.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
M. Sassoe-Pognetto and O. P. Ottersen
Organization of Ionotropic Glutamate Receptors at Dendrodendritic Synapses in the Rat Olfactory Bulb
J. Neurosci., March 15, 2000; 20(6): 2192 - 2201.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
N. E. Schoppa, J. M. Kinzie, Y. Sahara, T. P. Segerson, and G. L. Westbrook
Dendrodendritic Inhibition in the Olfactory Bulb Is Driven by NMDA Receptors
J. Neurosci., September 1, 1998; 18(17): 6790 - 6802.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online