HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 92/5/3085    most recent 00349.2004v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (23) Citing Articles via Google Scholar Google Scholar Articles by Heinbockel, T. Articles by Ennis, M. Search for Related Content PubMed PubMed Citation Articles by Heinbockel, T. Articles by Ennis, M.

Regulation of Main Olfactory Bulb Mitral Cell Excitability by Metabotropic Glutamate Receptor mGluR1

¹Department of Physiology and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201; ²Department of Anatomy, Howard University College of Medicine, Washington DC 20059; ³Department of Physiology, University of Otago, Dunedin, 9001 New Zealand; ⁴GlaxoSmithKline Experimental Research, Institut de Biologie Cellulaire et de Morphologic, 1228 Lausanne, Switzerland; and ⁵Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163

Submitted 5 April 2004; accepted in final form 21 June 2004

In the rodent main olfactory bulb (MOB), mitral cells (MCs) express high levels of the group I metabotropic glutamate receptor (mGluR) subtype, mGluR1. The significance of this receptor in modulating MC excitability is unknown. We investigated the physiological role of mGluR1 in regulating MC activity in rat and mouse MOB slices. The selective group I agonist (RS)-3,5-dihydroxyphenylglycine (DHPG), but not group II or III agonists, induced potent, dose-dependent, and reversible depolarization and increased firing of MCs. These effects persisted in the presence of blockers of fast synaptic transmission, indicating that they are due to direct activation of mGluRs on MCs. Voltage-clamp recordings showed that DHPG elicited a voltage-dependent inward current consisting of multiple components sensitive to potassium and calcium channel blockade and intracellular calcium chelation. MC excitatory responses to DHPG were absent in mGluR1 knockout mice but persisted in mGluR5 knockout mice. Broad-spectrum LY341495, MCPG, as well as preferential mGluR1 LY367385 antagonists blocked the excitatory effects of DHPG and also potently modulated MC spontaneous and olfactory nerve-evoked excitability. mGluR antagonists altered spontaneous membrane potential bistability, increasing the duration of the up and down states. mGluR antagonists also substantially attenuated MC responses to sensory input, decreasing the probability and increasing the latency of olfactory nerve-evoked spikes. These findings suggest that endogenous glutamate tonically modulates MC excitability and responsiveness to olfactory nerve input, and hence the operation of the MOB circuitry, via activation of mGluR1.

This article has been cited by other articles:

				H.-W. Dong, A. Hayar, J. Callaway, X.-H. Yang, Q. Nai, and M. Ennis Group I mGluR Activation Enhances Ca2+-Dependent Nonselective Cation Currents and Rhythmic Bursting in Main Olfactory Bulb External Tufted Cells J. Neurosci., September 23, 2009; 29(38): 11943 - 11953. [Abstract] [Full Text] [PDF]

				M. L. Fletcher, A. V. Masurkar, J. Xing, F. Imamura, W. Xiong, S. Nagayama, H. Mutoh, C. A. Greer, T. Knopfel, and W. R. Chen Optical Imaging of Postsynaptic Odor Representation in the Glomerular Layer of the Mouse Olfactory Bulb J Neurophysiol, August 1, 2009; 102(2): 817 - 830. [Abstract] [Full Text] [PDF]

				F. Ferraguti, L. Crepaldi, and F. Nicoletti Metabotropic Glutamate 1 Receptor: Current Concepts and Perspectives Pharmacol. Rev., December 1, 2008; 60(4): 536 - 581. [Abstract] [Full Text] [PDF]

				E. Chaigneau, P. Tiret, J. Lecoq, M. Ducros, T. Knopfel, and S. Charpak The Relationship between Blood Flow and Neuronal Activity in the Rodent Olfactory Bulb J. Neurosci., June 13, 2007; 27(24): 6452 - 6460. [Abstract] [Full Text] [PDF]

				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]

				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]

				T. Heinbockel, K. A. Hamilton, and M. Ennis Group I Metabotropic Glutamate Receptors Are Differentially Expressed by Two Populations of Olfactory Bulb Granule Cells J Neurophysiol, April 1, 2007; 97(4): 3136 - 3141. [Abstract] [Full Text] [PDF]

				D. De Saint Jan and G. L. Westbrook Disynaptic Amplification of Metabotropic Glutamate Receptor 1 Responses in the Olfactory Bulb J. Neurosci., January 3, 2007; 27(1): 132 - 140. [Abstract] [Full Text] [PDF]

				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]

				T. Heinbockel, N. Laaris, and M. Ennis Metabotropic Glutamate Receptors in the Main Olfactory Bulb Drive Granule Cell-Mediated Inhibition J Neurophysiol, January 1, 2007; 97(1): 858 - 870. [Abstract] [Full Text] [PDF]

				D. B. Rubin and T. A. Cleland Dynamical Mechanisms of Odor Processing in Olfactory Bulb Mitral Cells J Neurophysiol, August 1, 2006; 96(2): 555 - 568. [Abstract] [Full Text] [PDF]

				Q. Yuan and T. Knopfel Olfactory Nerve Stimulation-Evoked mGluR1 Slow Potentials, Oscillations, and Calcium Signaling in Mouse Olfactory Bulb Mitral Cells J Neurophysiol, May 1, 2006; 95(5): 3097 - 3104. [Abstract] [Full Text] [PDF]

				Q. Yuan and T. Knopfel Olfactory Nerve Stimulation-Induced Calcium Signaling in the Mitral Cell Distal Dendritic Tuft J Neurophysiol, April 1, 2006; 95(4): 2417 - 2426. [Abstract] [Full Text] [PDF]

				M. Ennis, M. Zhu, T. Heinbockel, and A. Hayar Olfactory Nerve-Evoked, Metabotropic Glutamate Receptor-Mediated Synaptic Responses in Rat Olfactory Bulb Mitral Cells J Neurophysiol, April 1, 2006; 95(4): 2233 - 2241. [Abstract] [Full Text] [PDF]

				H. Mutoh, Q. Yuan, and T. Knopfel Long-Term Depression at Olfactory Nerve Synapses J. Neurosci., April 27, 2005; 25(17): 4252 - 4259. [Abstract] [Full Text] [PDF]

				D. De Saint Jan and G. L. Westbrook Detecting Activity in Olfactory Bulb Glomeruli with Astrocyte Recording J. Neurosci., March 16, 2005; 25(11): 2917 - 2924. [Abstract] [Full Text] [PDF]