Fig. 3
From: Direct neurotransmitter activation of voltage-gated potassium channels
GABA directly opens KCNQ2/3 channels. All error bars in figure indicate SEM. a TEVC of water-injected Xenopus laevis oocytes showing no effect of GABA (100 µM) on endogenous currents or (lower right) resting membrane potential (EM) (n = 4–5). b TEVC of Xenopus laevis oocytes expressing KCNA1 (Kv1.1) showing no effect of GABA (1 mM) on peak current (left) or normalized tail current (right) (n = 4). c–f GABA effects on KCNQ2/3 in oocytes do not require GABAB receptor activity. Mean KCNQ2/3 tail currents in oocytes showing GABA activates KCNQ2/3 in the presence of pertussis toxin (2 µg/ml), saclofen (100 µM), or CGP55845 (100 µM) and that neither baclofen (100 µM), saclofen, nor CGP55845 alter KCNQ2/3 current independently (n = 5–7). g Upper, tail current; lower, normalized conductance; showing mean GABA response of oocyte-expressed KCNQ2/KCNQ3-W265L (n = 5). h Upper, tail current; lower, normalized conductance; showing mean GABA response of oocyte-expressed KCNQ2-W236L/KCNQ3-W265 (Q2/Q3-WL/WL) (n = 5). i Mean current fold-changes (upper) and dose responses (lower) for channels as indicated; KCNQ2/KCNQ3 results (purple line) and KCNQ3* results (red line) from Fig. 2 shown for comparison; n = 5–10. j Mean 3H-GABA binding for KCNQ2/3 versus KCNQ2-W236L/KCNQ3-W265L channels expressed in Xenopus oocytes; n = 73 (Q2/Q3), 29 (KCNQ2-W236L/KCNQ3-W265L) in two to four batches of oocytes; ****P < 0.0001
