Figure 3. The mimetic peptide ¹⁰panx1 inhibits ethidium bromide uptake but no I_Cl,swell.

A.- P2X₇-transfected HEK-293 cells were pre-incubated during 30 minutes with 500 μM ¹⁰panx1 in hypertonic SPG solution. Fluorescence time course of a representative cell (n=4) after the pre-incubation period is shown. In the presence of ¹⁰panx1 (cross-hatched bar) cell was stimulated with 2.5 mM ATP (black bar). ATP and ¹⁰panx1 peptide were then washed out and a second ATP stimulation was applied. B.- Representative time courses of I_Clswell at +80 mV of non-transfected HEK-293 cell. Cell was exposed to hypertonic SPG solution and then two consecutive challenges with hypotonic SPG solution were applied (striped bars). Control cell (upper trace) was not exposed to ¹⁰panx1, while test cell (lower trace) were pre-incubated during 30 minutes with 500 μM ¹⁰panx1 in hypertonic SPG solution; the cell remained in the presence of the peptide (cross-hatched bar) until the end of the first hypotonic challenge. Bar graphs.- Left: I_Clswell amplitude in control and peptide treated cells evoked by the first hypotonic challenge. Right: slope ratio; slopes were calculated from the activation phase of the time courses evoked by the second (slope 2) and first hypotonic challenges (slope 1). C=Control; P=peptide-treated cells; n=5 for both experimental groups.