Kavain, the Major Constituent of the Anxiolytic Kava Extract, Potentiates GABAA Receptors: Functional Characteristics and Molecular Mechanism
Fig 2
Kavain potentiates GABAARs with no apparent subtype selectivity.
(A) Representative traces demonstrating kavain (10–300 μM) enhancing current elicited by 10 μM GABA (EC3) at α1β2γ2L GABAARs in a concentration-dependent manner. (B) Representative traces of current responses elicited by a maximal concentration of GABA (10 mM), in comparison to 300 μM kavain alone. (C) Top panel, Potentiation of GABA-elicited currents (EC3-7) at α1β2, β2γ2L, αxβ2γ2L (x = 1, 2, 3 and 5) and α1βxγ2L (x = 1, 2 and 3) GABAARs by 300 μM kavain. At α4β2δ GABAARs, the GABA control (1 μM) corresponds to an EC30. Data are presented as mean ± SEM. Numbers in bars indicate the number of experiments. No significant difference was found for kavain potentiation at these receptor subtypes (Tukey’s test; p > 0.05 for all pairwise comparisons). Bottom panel, Superimposed current traces of GABA alone (black) and GABA in combination with 300 μM kavain (red) at the corresponding receptor subtypes. The black bars above the traces indicate duration of drug application.