Local pH values of both intra- and extracellular liquids can be regulated by a number of mechanisms including membrane transport and metabolism. It is known that the changes of extracellular pH accompanying physiological and pathological processes are sufficient to affect several important structures such as ionic channels, transporters, receptors etc. In particular, several reports indicate that GABAA receptor is strongly modulated by this factor. The effect of pH application of ultrafast perfusion system allowed to explore the mechanisms of pH effect on GABAA receptors in neurons. It is concluded that changes in pH exert their effects by allosteric modulation of GABAA receptors.