The rate of K+ flux (1/τ) was determined by fitting the normalized fluorescence decay with a single exponential (Eq. 2):2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${F}_{N}(t)={F}_{0}{e}^{\frac{-t}{\tau }}+C$$\end{document}FN(t)=F0e−tτ+Cwhere Fo is the amplitude, 1/τ is the rate, and C is a constant. In experiments where it was not possible to fit the decay, the amplitude of the fluorescence just prior to adding valinomycin (1190 s) was used to calculate the fractional inhibition of K+ flux.
