The Journal of Neurophysiology Vol. 79 No. 2 February 1998, pp. 1124-1126
Copyright ©1998 The American Physiological Society

RAPID COMMUNICATION

Zn²⁺ Blocks the NMDA- and Ca²⁺-Triggered Postexposure Current I_pe in Hippocampal Pyramidal Cells

Qiang X. Chen, Katherine L. Perkins, and Robert K. S. Wong

Department of Pharmacology, State University of New York Health Science Center, Brooklyn, New York 11203

Chen, Qiang X., Katherine L. Perkins, and Robert K. S. Wong. Zn²⁺ blocks the NMDA- and Ca²⁺-triggered postexposure current I_pe in hippocampal pyramidal cells. J. Neurophysiol. 79: 1124-1126, 1998. Whole cell voltage-clamp recordings from acutely isolated hippocampal CA1 pyramidal cells from adult guinea pigs were used to evaluate divalent cations as possible blockers of the postexposure current (I_pe). I_pe is a cation current that is triggered by the rise in intracellular Ca²⁺ concentration that occurs after the application of a toxic level of N-methyl-D-aspartate (NMDA). Once triggered, I_pe continues to grow until death of the neuron occurs. I_pe may be a critical link between transient NMDA exposure and cell death. I_pe was blocked by micromolar concentrations of Zn²⁺. The Zn²⁺ effect had an IC₅₀ of 64 µM and saturated at 500 µM. Prolonged Zn²⁺ block of I_pe revealed that the maintenance of a steady I_pe is not dependent on I_pe-mediated Ca²⁺ influx but that the continuous growth in I_pe is dependent on I_pe-mediated Ca²⁺ influx. The availability of an effective blocker of I_pe should facilitate the investigation of the intracellular activation pathway of I_pe and the role of I_pe in neuronal death.

This article has been cited by other articles:

				C. M. Norris, E. M. Blalock, O. Thibault, L. D. Brewer, G. V. Clodfelter, N. M. Porter, and P. W. Landfield Electrophysiological Mechanisms of Delayed Excitotoxicity: Positive Feedback Loop Between NMDA Receptor Current and Depolarization-Mediated Glutamate Release J Neurophysiol, November 1, 2006; 96(5): 2488 - 2500. [Abstract] [Full Text] [PDF]

				J. A. Connor and R. J. Cormier Cumulative Effects of Glutamate Microstimulation on Ca2+ Responses of CA1 Hippocampal Pyramidal Neurons in Slice J Neurophysiol, January 1, 2000; 83(1): 90 - 98. [Abstract] [Full Text] [PDF]