Skip to main content
. 2006 Mar 20;103(13):5149–5154. doi: 10.1073/pnas.0600847103

Fig. 4.

Fig. 4.

BTX blocks chloride influx in a GABAAR β3-expressing HEK 293 cell line. (a) Micrographs of cells incubated with the chloride sensor MEQ. (Upper) In cells stably transfected with GABAAR β3, MEQ fluorescence decreases when the extracellular chloride concentration is increased. The decrease is blocked by BTX. (Lower) Untransfected control HEK 293 cells show minimal response to changes in extracellular chloride concentration. (Scale bar, 5 μm.) (b) Quantitation of fluorescent signals from the experiment in a. •, control; ▴, GABAAR. Arrows show correspondence between micrographs in a and points in b. (c) Average MEQ fluorescence intensity in media containing 5 mM or 115 mM Cl− in the presence or absence of 1 μM BTX. Measurements in 115 mM Cl− were made 5 min after switching from 5 mM. Bars show mean ± SEM of measurements from 10–20 cells from five experiments.