Fig. 4.

GABA and β-alanine bind at different rates relative to SR-95531. A, Simultaneous application of equal concentrations of GABA and SR-95531 activates 11% of the patch current evoked by GABA alone, suggesting that the antagonist occupied many receptors before GABA could bind. B, Simultaneous application of β-alanine at a concentration a thousand times higher than that of SR-95531 activates only 28% of the current evoked by β-alanine alone, suggesting that β-alanine binds much more slowly than GABA, relative to SR-95531.