Simulation of intracellular Ca 2+ oscillation in a sympathetic neurone

Abstract

Three different theoretical models were considered for the mechanism of the oscillation of the intracellular free Ca 2+ ([Ca 2+] i) linked to the K + conductance of the plasma membrane ( G K) observed in bullfrog sympathetic ganglion cells. The models assumed a Ca 2+-induced Ca 2+ release mechanism, an active Ca 2+ uptake mechanism at a Ca 2+ reservoir site in the ganglion cell, and a Michaelis—Menten type relationship between [Ca 2+] i and G K. Including both active and passive Ca 2+ transport mechanisms at the plasma membrane, either a one-compartment model or a two-compartment model for the intracellular Ca 2+ store reconstructed successfully the [Ca 2+] i oscillation and rhythmic membrane hyperpolarizations observed in the ganglion cell, and simulated most of their characteristics. On the other hand, a two-compartment model disregarding of Ca 2+ transport at the plasma membrane failed to reproduce the oscillations of [Ca 2+] i and membrane potential.