Fig. 2

Ca²⁺ influx by GABAergic neural inputs in an immature neuron in immature neurons, NKCC1 is more active than KCC2 and intracellular Cl⁻ concentration is maintained at a relatively high level. GABA released from GABAergic interneurons opens GABA_A receptor Cl⁻ channels and Cl⁻ efflux results in the depolarization of the neuron. Depolarization opens voltage dependent calcium channels (VDCC) and removes bound Mg²⁺ from NMDA receptors, resulting in Ca²⁺ influx through VDCCs and glutamate-activated NMDA receptors. (The glycine binding site on NMDA receptors has been omitted)