Interaction Analysis of Membrane Action Potential and Intercellular Free Calcium Ion Density with Simultaneous Fluorescence Measurement

Abstract

This paper investigates an optical method which measures cytoplasmic membrane action potential and intercellular free calcium ion density at the same time and point. The measurement (simultaneous fluorescence measurement) is brought to realization with two kind of fluorescent dyes. The multi-dyeing of voltage-sensitive dye and fluorescent calcium indicator is considered, and spectrum characteristic of these dyes is examined.
The experiment is gone as follows. First, absorption spectrum of Rhod2 and Fluo3, which fluorescent calcium indicator can be pumped by visible light, is measured. These solutions are composed of distilled water, 5[μM] dye, and 50[mM] CaCl2. The result suggests that Rhod2 and Fluo3 can be pumped with Ar or Kr laser and Ar laser for high efficiency respectively. Second, Fluorescence spectrum of Rhod2 an.d Fluo3 is measured. Absorption spectrum and fluorescence spectrum of WW781, which voltage-sensitive dye can be pumped, is measured too. Rhod2 solution and Fluo3 solution are prepared as has been pointed out. WW781 solution is made up of ethanol and 0.025[mg/ml] WW781. These spectrums show that simultaneous fluorescence measurement of cytoplasmic membrane action potential and intercellular free calcium density with WW781 and Fluo3 is possible.