Brownian dynamic model of the glycine receptor chloride channel: effect of the position of charged amino acids on ion membrane currents.

Glycine is the major inhibitory neurotransmitter in the brainstem and spinal cord, where it participates in a variety of motor and sensory functions. It activates a special type of ligand-gated membrane receptor, which provides for Cl- ion conductance of the neuronal membrane. Computer simulations of a single-channel current through this receptor have been carried out on the basis of Brownian (Langevin) dynamics. The dependence of the currents on pore diameter and the location of the charged amino acid residues have been obtained. It has been shown that the presence and the symmetry of the filter-forming residues determined not only the ion-selectivity of the channel but also increased transmembrane anion current.