The Involvement of Alkaline Earth Cations in the Control of Acetylcholine Release

  • Eugene M. Silinsky


Neuroscientists allured by the mechanisms of transmitter secretion have at their disposal fortuitous electrophysiological deflections which allow a direct, moment to moment assay for acetylcholine (ACh) secretion. Specifically, the ratio of the amplitudes of the electrical events associated with neurally-evoked ACh release (end-plate potentials, EPFs) to the spontaneous potentials (miniature end-plate potentials, MEPPs) serves as a reliable estimate of the mean number of ACh quanta released synchronously by a nerve impulse (M, del Castillo and Katz, 1954). Extracellular Ca ions are essential for the process of evoked ACh release (for reviews see Katz, 196?; Silinsky, 1985). Specifically Ca must be equlibrated with a receptor near the external surface of the calcium channel prior to depolarization to support transmitter secretion. Depolarization, normally provided by the action potential, opens these voltage-sensitive calcium channels and Ca enters the nerve terminal cytoplasm down its electrochemical gradient. Once in the cytoplasm, Ca reduces a series of energy barriers and promotes ACh release.


Synaptic Vesicle Transmitter Release Motor Nerve Terminal Transmitter Secretion MEPP Frequency 
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Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • Eugene M. Silinsky
    • 1
  1. 1.Department of PharmacologyNorthwestern University Medical SchoolChicagoUSA

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