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: 96/2/919    most recent 00258.2006v1 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 (9) Citing Articles via Google Scholar Google Scholar Articles by Fedirko, N. Articles by Chesler, M. Search for Related Content PubMed PubMed Citation Articles by Fedirko, N. Articles by Chesler, M.

INNOVATIVE METHODOLOGY

Fabrication and Use of High-Speed, Concentric H⁺- and Ca²⁺-Selective Microelectrodes Suitable for In Vitro Extracellular Recording

Department of Neurosurgery, and Department of Physiology and Neuroscience, New York University School of Medicine, New York, New York

Submitted 9 March 2006; accepted in final form 26 April 2006

Ion-selective microelectrodes (ISMs) have been used extensively in neurophysiological studies. ISMs selective for H⁺ and Ca²⁺ are notable for their sensitivity and selectivity, but suffer from a slow response time, and susceptibility to noise because of the high electrical resistance of the respective ion exchange cocktails. These drawbacks can be overcome by using a "coaxial" or "concentric" inner micropipette to shunt the bulk of the ion exchanger resistance. This approach was used decades ago to record extracellular [Ca²⁺] transients in cat cortex, but has not been subsequently used. Here, we describe a method for the rapid fabrication of concentric pH- and Ca²⁺-selective microelectrodes useful for extracellular studies in brain slices or other work in vitro. Construction was simplified compared with previous implementations, by using commercially available, thin-walled borosilicate glass, drawing an outer barrel with a rapid taper (similar to a patch pipette), and by use of a quick and reliable silanization procedure. Using a piezoelectric stepper to effect a rapid solution change, the response time constants of the concentric pH and Ca²⁺-electrodes were 14.9 ± 1.3 and 5.3 ± 0.90 ms, respectively. Use of these concentric ISMs is demonstrated in rat hippocampal slices. Activity-dependent, extracellular pH, and [Ca²⁺] transients are shown to arise two- to threefold faster, and attain amplitudes two- to fourfold greater, when recorded by concentric versus conventional ISMs. The advantage of concentric ISMs for studies of ion transport and ion diffusion is discussed.

This article has been cited by other articles:

				E. Sykova and C. Nicholson Diffusion in Brain Extracellular Space Physiol Rev, October 1, 2008; 88(4): 1277 - 1340. [Abstract] [Full Text] [PDF]

				S. Makani and M. Chesler Endogenous Alkaline Transients Boost Postsynaptic NMDA Receptor Responses in Hippocampal CA1 Pyramidal Neurons J. Neurosci., July 11, 2007; 27(28): 7438 - 7446. [Abstract] [Full Text] [PDF]

				N. Fedirko, M. Avshalumov, M. E. Rice, and M. Chesler Regulation of Postsynaptic Ca2+ Influx in Hippocampal CA1 Pyramidal Neurons via Extracellular Carbonic Anhydrase J. Neurosci., January 31, 2007; 27(5): 1167 - 1175. [Abstract] [Full Text] [PDF]