Using whole cell patch-clamp recording to record responses to rapidly applied GABA in the absence and presence of the three putative antagonists in turn we found that SKF 96365 (1-100 渭M) and FF (1-100 渭M) significantly inhibited GABA responses of recombinant human 伪1尾2纬2 GABAA receptor stably expressed in HEK293 cells with IC50 values of 13.4 卤 5.1 and 1.9 卤 1.4 渭M, respectively, suppressing the maximal response to GABA at all concentrations used in a manner consistent with a non-competitive mode of action. SKF 96365 and FF also both significantly reduced desensitisation and prolonged the deactivation kinetics of the receptors to GABA (1 mM; P < 0.05). 2-APB (10-1000 渭M) also inhibited responses to GABA at all concentrations used with an IC50 value of 16.7 卤 5.4 渭M (n = 3-5) but had no significant effect on the activation, desensitisation or deactivation kinetics of the GABA responses.
Taken together this investigation revealed that these widely utilised TRP channel antagonists display significant 鈥榦ff-target鈥?effects at concentrations that are routinely used for the study of TRP channel function in numerous biological systems and as such, data which is obtained utilising these compounds should be interpreted with caution.