Accession Number : ADA195092

Title :   Gating Kinetics and Ion Transfer in Channels of Nerve Membrane.

Descriptive Note : Annual rept. Nov 86-Nov 87,

Corporate Author : TEXAS UNIV MEDICAL BRANCH AT GALVESTON DEPT OF PHYSIOLOGY AND BIOPHYSICS

Personal Author(s) : Fishman, Harvey M

PDF Url : ADA195092

Report Date : 21 Oct 1987

Pagination or Media Count : 11

Abstract : The ultimate objective of this project is to obtain an electrochemical description of the molecular processes underlying the movement of ions across nerve membranes during excitation of a nerve fiber. The short-term objectives are to obtain fundamental information on the processes of ion transfer in sodium and potassium channels known as gating (electric-field initiated alteration of the membrane to the conduction of specific ions) and conductance (the passage of ions through a channel after ions gain access to a channel). The kinetics of gated channels derived from analysis of stochastic (microscopic) current fluctuations and those derived from macroscopic determinations will be compared to ascertain whether an assumed relationship exists. Furthermore, the macroscopic gating kinetics of Na and K channels derived from step clamp transients will be compared with those derived in steady state via small-amplitude admittance measurements to ascertain if kinetic determinations are time invariant. Conductance studies will focus on the voltage-sensitivity of the Na channel conductance and whether this could arise from channel blockage by calcium or hydrogen ions, multiple conducting states of channels, or from a heterogeneous population of channels. Keywords: Nerve transmission.

Descriptors :   *ELECTROCHEMISTRY, *MEMBRANES(BIOLOGY), *NEUROCHEMISTRY, CLAMPS, CONDUCTIVITY, HETEROGENEITY, HYDROGEN, INVARIANCE, IONS, KINETICS, MOLECULES, NERVE FIBERS, NERVE TRANSMISSION, NERVES, POPULATION, POTASSIUM, SODIUM, STEADY STATE, TIME, TRANSFER, TRANSIENTS, VARIATIONS, MOLECULE MOLECULE INTERACTIONS, ION EXCHANGE

Subject Categories : Biochemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE