Figure 3.

Extracellular application of mefenamic acid inhibits TRPM3 currents in transfected HEK293 cells. (A) Current of TRPM3 at membrane potentials of −80 (lower trace) and +80 mV (upper trace) during the application of the TRPM3 activator pregnenolone sulphate (35 µM) and the inhibition of the current after application of mefenamic acid (25 µM). (B) Current–voltage relationship from experiments shown in (A). Mefenamic acid inhibited the inward current almost completely, although a small outward current is still visible. (C) Current recorded from a TRPM3-expressing cell, experiments performed as in (A) with the modification that mefenamic acid (35 µM) was added into the pipette solution. (D) Current–voltage relationship from the experiment shown in (C). Intracellularly applied mefenamic acid had no impact on the pregnenolone sulphate-induced current.