Fig. 2.

Measurements of [K⁺]_out in WT and thetrpl³⁰²;trp³⁴³mutant show that only the second and large phase of the response to anoxia arise from activation of TRP and TRPL channels.a, Extracellular voltage change (ERG,top panel, in black) and potentiometric measurements with a K⁺-selective microelectrode (E_K, bottom panel, inred) in response to orange lights and anoxia, in wild-type (WT) Drosophila. On average, the maximal Δ[K⁺]_out during anoxia was 7.26 ± 1.83 mm (n= 4), assuming that [K⁺]_out in the dark is 4 mm (Sandler and Kirschfeld, 1991). The calibration applies for both the ERG and the potentiometric measurements with the K⁺-selective microelectrode.b, The experiments of a were repeated in the double mutanttrpl³⁰²;trp³⁴³. Note that there is no response to light, and the second phase of the response to anoxia is absent. On average, the maximal Δ[K⁺]_out was 2.64 ± 0.54 mm (n = 4) during anoxia.