Journal of Neurophysiology, Vol 76, Issue 4 2804-2807, Copyright © 1996 by APS

ARTICLES

Temporal resolution of activity-dependent pH shifts in rat hippocampal slices

J. A. Gottfried and M. Chesler
Department of Physiology and Neuroscience, New York University Medical Center, New York 10016, USA.

1. The rise time of activity-dependent extracellular pH shifts was measured in the CA1 stratum radiatum of rat hippocampal slices by recording pH-sensitive fluorescence of a fluorescein-conjugated dextran. Optical data were compared with simultaneous pH microelectrode recordings. 2. The pH shifts generated by CO2 or by stimulation of the Schaffer collaterals were paralleled by shifts in fluorescence emissions at 535 nm when the probe was excited with 490-nm light (delta F490). Emissions at 535 nm induced by 440-nm light were unchanged in these paradigms. 3. A train of three stimuli at 100 Hz was repeated at 30-s intervals and the stimulus-triggered delta F490 was averaged. The mean rise time of the delta F490 was 69 +/- 24 (SE) ms (range 20-200 ms, n = 6). The mean increase in emission was 0.75 +/- 0.22% of baseline, associated with a pH microelectrode response of +0.06 +/- 0.02 unit pH. 4. These data demonstrate that synaptically evoked alkaline transients develop within tens of milliseconds. The occurrence of the alkalinization in the same time frame as excitatory postsynaptic currents indicates that these pH shifts arise with sufficient speed to modulate synaptic transmission.

This article has been cited by other articles:

				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]

				N. Fedirko, N. Svichar, and M. Chesler Fabrication and Use of High-Speed, Concentric H+- and Ca2+-Selective Microelectrodes Suitable for In Vitro Extracellular Recording J Neurophysiol, August 1, 2006; 96(2): 919 - 924. [Abstract] [Full Text] [PDF]

				C.-K. Tong, K. Chen, and M. Chesler Kinetics of Activity-Evoked pH Transients and Extracellular pH Buffering in Rat Hippocampal Slices J Neurophysiol, June 1, 2006; 95(6): 3686 - 3697. [Abstract] [Full Text] [PDF]

				M. CHESLER Regulation and Modulation of pH in the Brain Physiol Rev, October 1, 2003; 83(4): 1183 - 1221. [Abstract] [Full Text] [PDF]

				G. S. Mitchell and S. M. Johnson Plasticity in Respiratory Motor Control: Invited Review: Neuroplasticity in respiratory motor control J Appl Physiol, January 1, 2003; 94(1): 358 - 374. [Abstract] [Full Text] [PDF]

				E. C. Ihle and D. K. Patneau Modulation of alpha -Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptor Desensitization by Extracellular Protons Mol. Pharmacol., April 13, 2001; 58(6): 1204 - 1212. [Abstract] [Full Text]

				M. de Curtis, A. Manfridi, and G. Biella Activity-Dependent pH Shifts and Periodic Recurrence of Spontaneous Interictal Spikes in a Model of Focal Epileptogenesis J. Neurosci., September 15, 1998; 18(18): 7543 - 7551. [Abstract] [Full Text] [PDF]