Fig. 5
From: Direct neurotransmitter activation of voltage-gated potassium channels
GABA activation is independent of and overrides muscarinic inhibition of KCNQ2/3 in Xenopus oocytes. All error bars in figure indicate SEM. a Mean dose response for acetylcholine (ACh) on KCNQ2/3 activity in oocytes (n = 5). b Mean effects versus voltage for ACh or atropine alone or in combination on KCNQ2/3 activity in oocytes (n = 5). c Lack of effects of dopamine (100 µM) on KCNQ2/3 mean tail currents in oocytes (n = 6). d Atropine blocks KCNQ2/3 inhibition by ACh (measured using tail currents in oocytes; n = 5). e Lack of effects of atropine (100 µM) on KCNQ2/3 mean tail currents in oocytes (n = 5). f Atropine does not prevent GABA activation of KCNQ2/3 measured via tail currents in oocytes (n = 5). Left, mean tail currents, right, current fold-change versus voltage for GABA + atropine versus no drugs. g GABA prevents inhibition of KCNQ2/3 by ACh, measured via tail currents in oocytes (n = 5). Left, mean tail currents, right, current fold-change versus voltage for GABA + ACh versus no drugs. h GABA (10 µM) effects on KCNQ2/3 in oocytes are not prevented by partial depletion/inhibition of synthesis of PIP2 using wortmannin (30 µM for 3 h) (n = 5). Left, mean tail current; right, GABA dose response at −60 mV; (n = 5). i GABA (100 µM) has no effect on KCNQ1/KCNE1. Left, averaged traces; right, mean tail currents (n = 6). j GABA (100 µM) does not alter resting membrane potential (EM) of unclamped oocytes expressing KCNQ1-KCNE1 (n = 6)
