Integer multiple spiking induced by Gaussian white noise in the stochastic Chay system may occur near a subcritical Hopf bifurcation of the corresponding deterministic system without external periodic forcing. The deterministic Chay system near the subcritical Hopf bifurcation can exhibit a damped subthreshold oscillation of membrane potential, and can easily fire a spike in response to some kinds of weak pulses. Therefore, on account of the characteristic of Gaussian white noise, it can be shown that the deterministic Chay system supplied with certain weak pulses can fire integer multiple spiking similar to that in the corresponding stochastic system. Furthermore, on the light of the characteristic of the unstable limit cycle "before" a subcritical Hopf bifurcation in the deterministic Chay model, it can be explained that integer multiple spiking only appears in a certain range of the parameter VK.