FIGURE 7.

NKCC1-mediated Tl⁺ (thallium) uptake in single isolated DRG neurons. DRG neurons were loaded with the thallium-sensitive dye FluxOR. FluxOR fluorescence (approximate fluorescence excitation and emission: 488/525 nm) increases upon addition of 2.8 mm Tl₂SO₄ to the external medium. A, photographs of DRG neurons showing increase in fluorescence after a 6 min addition of thallium. The two photographs on the left are differential interference contrast (DIC) pictures, whereas the four photographs on the right are fluorescence pictures. B, fluorescence intensity as a function of time. The top trace represents the fluorescence signal average of 26 DRG neurons under regular conditions. The bottom trace represents the fluorescence signal average of 21 DRG neurons incubated in the presence of 20 μm bumetanide. The difference between the two curves represents the bumetanide-sensitive component of the Tl⁺ uptake, mediated by NKCC1.