 Since NALCN sodium leak channels appear to contribute to the depolarization of neurons, their regulation by G-protein coupled receptors may be vital for the alteration of bursting and breathing rhythms.Other inward currents that help generate intrinsic spiking and bursting in pacemaker neurons are the calcium current and calcium-activated nonspecific currents (ICAN).When a neuron becomes depolarized, voltage gated calcium channels become activated and calcium is able to flow into the cell which usually leads to the release of neurotransmitters.