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


     

J Neurophysiol 90: 3341-3351, 2003. First published July 16, 2003; doi:10.1152/jn.00560.2003
0022-3077/03 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
90/5/3341    most recent
00560.2003v1
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 ISI Web of Science
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 ISI Web of Science (13)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Pinato, G.
Right arrow Articles by Midtgaard, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Pinato, G.
Right arrow Articles by Midtgaard, J.

Regulation of Granule Cell Excitability by a Low-Threshold Calcium Spike in Turtle Olfactory Bulb

Giulietta Pinato and Jens Midtgaard

Division of Neurophysiology, Department of Medical Physiology, University of Copenhagen, DK-2200 N Copenhagen, Denmark

Submitted 11 June 2003; accepted in final form 10 July 2003

Granule cells excitability in the turtle olfactory bulb was analyzed using whole cell recordings in current- and voltage-clamp mode. Low-threshold spikes (LTSs) were evoked at potentials that are subthreshold for Na spikes in normal medium. The LTSs were evoked from rest, but hyperpolarization of the cell usually increased their amplitude so that they more easily boosted Na spike initiation. The LTS persisted in the presence of TTX but was antagonized by blockers of T-type calcium channels. The voltage dependence, kinetics, and inactivation properties of the LTS were characteristic of a low-threshold calcium spike. The threshold of the LTS was slightly above the resting potential but well below the Na spike threshold, and the LTS was often evoked in isolation in normal medium. Tetraethylammonium (TEA) and 4-aminopyridine (4-AP) had only minimal effects on the LTS but revealed the presence of a high-threshold Ca2+ spike (HTS), which was antagonized by Cd2+. The LTS displayed paired-pulse attenuation, with a timescale for recovery from inactivation of about 2 s at resting membrane potential. The LTS strongly boosted Na spike initiation; with repetitive stimulation, the long recovery of the LTS governed Na spike initiation. Thus the olfactory granule cells possess an LTS, with intrinsic kinetics that contribute to sub- and suprathreshold responses on a timescale of seconds. This adds a new mechanism to the early processing of olfactory input.

Address for reprint requests and other correspondence: J. Midtgaard, Division of Neurophysiology, Dept. of Medical Physiology, Univ. of Copenhagen, Blegdamsvej 3, DK-2200 N Copenhagen, Denmark (E-mail: j.midtgaard{at}mfi.ku.dk).




This article has been cited by other articles:


Home page
 J. Physiol.Home page
B.-J. Lin, T.-W. Chen, and D. Schild
Cell type-specific relationships between spiking and [Ca2+]i in neurons of the Xenopus tadpole olfactory bulb
J. Physiol., July 1, 2007; 582(1): 163 - 175.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
H.-W. Dong, A. Hayar, and M. Ennis
Activation of Group I Metabotropic Glutamate Receptors on Main Olfactory Bulb Granule Cells and Periglomerular Cells Enhances Synaptic Inhibition of Mitral Cells
J. Neurosci., May 23, 2007; 27(21): 5654 - 5663.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
J. B. Castro, K. R. Hovis, and N. N. Urban
Recurrent Dendrodendritic Inhibition of Accessory Olfactory Bulb Mitral Cells Requires Activation of Group I Metabotropic Glutamate Receptors
J. Neurosci., May 23, 2007; 27(21): 5664 - 5671.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
N. Laaris, A. Puche, and M. Ennis
Complementary Postsynaptic Activity Patterns Elicited in Olfactory Bulb by Stimulation of Mitral/Tufted and Centrifugal Fiber Inputs to Granule Cells
J Neurophysiol, January 1, 2007; 97(1): 296 - 306.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
V. Kapoor and N. N. Urban
Glomerulus-specific, long-latency activity in the olfactory bulb granule cell network.
J. Neurosci., November 8, 2006; 26(45): 11709 - 11719.
[Abstract] [Full Text] [PDF]

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
T. Zelles, J. D. Boyd, A. B. Hardy, and K. R. Delaney
Branch-Specific Ca2+ Influx from Na+-Dependent Dendritic Spikes in Olfactory Granule Cells
J. Neurosci., January 4, 2006; 26(1): 30 - 40.
[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. Neurophysiol.Home page
G. Pinato and J. Midtgaard
Dendritic Sodium Spikelets and Low-Threshold Calcium Spikes in Turtle Olfactory Bulb Granule Cells
J Neurophysiol, March 1, 2005; 93(3): 1285 - 1294.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2003 by the The American Physiological Society.