Fura 2 determination of [Ca2+]i in isolated perfused heart using R wave-gated electromechanical shutters.
We describe a novel and relatively inexpensive spectrofluorescence system that supplies rapidly alternating wavelengths to either a standard cuvette or an isolated perfused heart. Its use is illustrated by determining changes in cytosolic intracellular Ca2+ concentration ([Ca2+]i) by using the Ca(2+)-sensitive fluorescent dye fura 2 in a rabbit heart preparation. The system uses two precision electromechanical shutters (capable of gating with respect to the electrocardiographic R wave for signal averaging) allowing alternate fura 2 excitation wavelengths (340 and 380 nm) without moving optical components and uses a fiber optic for conducting excitation and collecting epifluorescence. Sample recordings tracing the [Ca2+]i transient in an entire cardiac cycle and in capturing specific isolated regions (diastole and systole) of the cycle are presented. Limitations of this low-cost but easily implemented system are discussed.
Chen
D P
DP
Division of Cardiothoracic Surgery, New England Deaconess Hospital, Boston, Massachusetts 02215.
Jimenez
E
E
Ataka
K
K
Levitsky
S
S
Feinberg
H
H
D000818:Animals; D002118:Calcium / Q000032:analysis*; D003600:Cytosol / Q000737:chemistry; D003971:Diastole; D004562:Electrocardiography; D005336:Fiber Optic Technology; D016257:Fura-2 / Q000032:analysis* / Q000737:chemistry; D066298:In Vitro Techniques; D008297:Male; D009206:Myocardium / Q000737:chemistry*; D055100:Optical Fibers; D011817:Rabbits; D012984:Software; D013050:Spectrometry, Fluorescence; D013599:Systole
D002118:Calcium; D016257:Fura-2