Fig. 6. Voltage-independent inhibition of the 5-HT₃ receptor currents by lamotrigine.

(A) Superimposed traces show the 5-HT₃ receptor currents evoked by 5-HT alone (3 µM, open bar, left) and co-application with lamotrigine (LTG, 30 µM, closed bar, right) at various holding potentials (from −50 mV to +30 mV, 20 mV interval). (B) Averaged data show the I~V relationship in the absence (○) and the presence of lamotrigine (●) (n=7). Data were normalized to the value of the peak amplitudes induced by 5-HT (3 µM, −50 mV) alone, which was set as a −1. (C) Averaged data show a fractional block of lamotrigine (I_5-HT+LTG/I_5-HT) as a function of holding potential. Each data represents mean±S.E.M.