Evaluation of the electrophysiological consequences of GABA removal from the synaptic cleft by Na+ ion transport-coupled neuronal uptake

Abstract The pre- and postsynaptic electrophysiological consequences of a carrier-mediated, Na + ion transport-coupled removal of γ-aminobutyric acid (GABA) from the relevant synaptic clefts are discussed. Assuming for the GABA internalization process a stoichiometry like GABA o +3Na o + +K o + ⇆GABA i +3Na i + +K o + and a synaptic cleft GABA maximal concentrated of 100 μM we calculated the presynaptic depolarization associated with GABA removal between 11.5 and 38.2 mV. At the postsynaptic level the effect appears to be less marked.