GEOMETRIC AND MANY-PARTICLE ASPECTS OF TRANSMITTER BINDING

We investigate the various reactivity patterns possible when several t ransmitter molecules, released at one side of a synaptic gap, diffuse and bind reversibly to a single receptor at the other end. In the fram ework of a one-dimensional approximation, the complete time, reactivit y, concentration and gap-width dependence are determined, using a rigo rous theoretical and computational approach to the many-body aspects o f this problem. The time dependence of the survival probability is fou nd to consist of up to four phases. These include a short delay follow ed by gaussian, power-law, and exponential decay phases. A rigorous ex pression is derived for the long-time exponent and approximate express ions are obtained for describing the short-time gaussian phase.