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: 91/2/946    most recent 00547.2003v1 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 ISI 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 ISI Web of Science (22) Citing Articles via Google Scholar Google Scholar Articles by Mangan, P. S. Articles by Kapur, J. Search for Related Content PubMed PubMed Citation Articles by Mangan, P. S. Articles by Kapur, J.

Factors Underlying Bursting Behavior in a Network of Cultured Hippocampal Neurons Exposed to Zero Magnesium

Department of Neurology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908

Submitted 5 June 2003; accepted in final form 25 September 2003

Factors contributing to reduced magnesium-induced neuronal action potential bursting were investigated in primary hippocampal cell culture at high and low culture density. In nominally zero external magnesium medium, pyramidal neurons from high-density cultures produced recurrent spontaneous action potential bursts superimposed on prolonged depolarizations. These bursts were partially attenuated by the NMDA receptor antagonist D-APV. Pharmacological analysis of miniature excitatory postsynaptic currents (EPSCs) revealed 2 components: one sensitive to D-APV and another to the AMPA receptor antagonist DNQX. The components were kinetically distinct. Participation of NMDA receptors in reduced magnesium-induced synaptic events was supported by the localization of the NR1 subunit of the NMDA receptor with the presynaptic vesicular protein synaptophysin. Presynaptically, zero magnesium induced a significant increase in EPSC frequency likely attributable to increased neuronal hyperexcitability induced by reduced membrane surface charge screening. Mean quantal content was significantly increased in zero magnesium. Cells from low-density cultures did not exhibit action potential bursting in zero magnesium but did show increased EPSC frequency. Low-density neurons had less synaptophysin immunofluorescence and fewer active synapses as determined by FM1-43 analysis. These results demonstrate that multiple factors are involved in network bursting. Increased probability of transmitter release presynaptically, enhanced NMDA receptor-mediated excitability postsynaptically, and extent of neuronal interconnectivity contribute to initiation and maintenance of elevated network excitability.

This article has been cited by other articles:

				H. P. Goodkin, S. Joshi, Z. Mtchedlishvili, J. Brar, and J. Kapur Subunit-Specific Trafficking of GABAA Receptors during Status Epilepticus J. Neurosci., March 5, 2008; 28(10): 2527 - 2538. [Abstract] [Full Text] [PDF]

				H. X. Zhang and L. L. Thio Zinc Enhances the Inhibitory Effects of Strychnine-Sensitive Glycine Receptors in Mouse Hippocampal Neurons J Neurophysiol, December 1, 2007; 98(6): 3666 - 3676. [Abstract] [Full Text] [PDF]

				L. M. Valor, P. Charlesworth, L. Humphreys, C. N. G. Anderson, and S. G. N. Grant Network activity-independent coordinated gene expression program for synapse assembly PNAS, March 13, 2007; 104(11): 4658 - 4663. [Abstract] [Full Text] [PDF]

				P. J. Jones, Y. Wang, M. D. Smith, N. J. Hargus, H. S. Eidam, H. S. White, J. Kapur, M. L. Brown, and M. K. Patel Hydroxyamide Analogs of Propofol Exhibit State-Dependent Block of Sodium Channels in Hippocampal Neurons: Implications for Anticonvulsant Activity J. Pharmacol. Exp. Ther., February 1, 2007; 320(2): 828 - 836. [Abstract] [Full Text] [PDF]

				R. E. Blair, L. S. Deshpande, S. Sombati, K. W. Falenski, B. R. Martin, and R. J. DeLorenzo Activation of the Cannabinoid Type-1 Receptor Mediates the Anticonvulsant Properties of Cannabinoids in the Hippocampal Neuronal Culture Models of Acquired Epilepsy and Status Epilepticus J. Pharmacol. Exp. Ther., June 1, 2006; 317(3): 1072 - 1078. [Abstract] [Full Text] [PDF]

				H. P. Goodkin, J.-L. Yeh, and J. Kapur Status Epilepticus Increases the Intracellular Accumulation of GABAA Receptors J. Neurosci., June 8, 2005; 25(23): 5511 - 5520. [Abstract] [Full Text] [PDF]

				C. Wyart, S. Cocco, L. Bourdieu, J.-F. Leger, C. Herr, and D. Chatenay Dynamics of Excitatory Synaptic Components in Sustained Firing at Low Rates J Neurophysiol, June 1, 2005; 93(6): 3370 - 3380. [Abstract] [Full Text] [PDF]

				P. S. Mangan, C. Sun, M. Carpenter, H. P. Goodkin, W. Sieghart, and J. Kapur Cultured Hippocampal Pyramidal Neurons Express Two Kinds of GABAA Receptors Mol. Pharmacol., March 1, 2005; 67(3): 775 - 788. [Abstract] [Full Text] [PDF]