Depolarizing action of GABA on neurons of the central nervous system during early postnatal development

Within the early period of mammalian ontogenic development, activation of GABAA receptors evokes in the central nervous system depolarization of the cellular membranes, instead of inhibition. In this review, we describe phenomenology and mechanisms underlying the effects related to this peculiarity, in particular a GABA-activated increase in the intracellular calcium concentration and oscillations of the latter in the hippocampal neuronal network. The physiological role of the GABA-mediated depolarizing synaptic activity (as a possible factor influencing formation of a glutamatergic synaptic network) is discussed.