Abstract

The release of a quantum from a nerve terminal is accompanied by the flow of extracellular current, which creates a field around the site of transmitter action. We provide a solution for the extent of this field for the case of a quantum released from a site on an amphibian motor-nerve terminal branch onto the receptor patch of a muscle fiber and compare this with measurements of the field using three extracellular electrodes. Numerical solution of the equations for the quantal potential field in cylindrical coordinates show that the density of the field at the peak of the quantal current gives rise to a peak extracellular potential, which declines approximately as the inverse of the distance from the source at distances greater than about 4 microm from the source along the length of the fiber. The peak extracellular potential declines to 20% of its initial value in a distance of about 6 microm, both along the length of the fiber and in the circumferential direction around the fiber. Simultaneous recordings of quantal potential fields, made with three electrodes placed in a line at right angles to an FM1-43 visualized branch, gave determinations of the field strengths in accord with the numerical solutions. In addition, the three electrodes were placed so as to straddle the visualized release sites of a branch. The positions of these sites were correctly predicted on the basis of the theory and independently ascertained by FM1-43 staining of the sites. It is concluded that quantal potential fields at the neuromuscular junction that can be used on Quantal potential fields around individual amphibian motor-nerve terminal active zones for the in silico rationally designed drug Peptide-mimic pharmacologic low mass predicted chemorecored poly-druggable-structure molecules for the possible potentiating of the efficient delivery of gene constructs through the internalization successes in experimental therapy of muscular dystrophies.

Keywords

Quantal potential fields; individual active zones; amphibian motor-nerve terminals; in silico; rationally designed; drug molecules; Peptide-mimic; pharmacologic low mass predicted; chemorecored; poly-druggable-structure; possible potentiating; efficient delivery; gene constructs; internalization successes; experimental therapy; muscular dystrophies.