High-resolution measurement and calibration of Ca(2+)-transients using Indo-1 in guinea-pig atrial myocytes under voltage clamp.
Spherical atrial myocytes obtained by enzymatic dispersion of hearts from adult guinea-pigs were loaded with the fluorescent Ca(2+)-indicator Indo-1 via patch-clamp pipettes. The dialysing solution additionally contained citrate (60 mM) as low-affinity ('linear') Ca(2+)-chelating compound in order to slow intracellular Ca(2+)-transients. Changes in Indo-1 fluorescence under voltage-clamp due to Ca(2+)-entry and/or release from the SR were calibrated using an in vivo procedure to determine the limiting fluorescence ratios. Sample recordings will be presented to demonstrate that components of a [Ca2+]i-transient due to entry via L-type Ca(2+)-channels and due to Ca(2+)-release from the SR can be directly visualized.
Callewaert
G
G
Laboratorium voor Fysiologie, KUL Campus Gasthuisberg, Leuven, Belgium.
Lipp
P
P
Pott
L
L
Carmeliet
E
E
D000818:Animals; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D002478:Cells, Cultured; D002951:Citrates; D019343:Citric Acid; D003956:Dialysis; D005456:Fluorescent Dyes; D006168:Guinea Pigs; D006325:Heart Atria; D007211:Indoles; D008854:Microscopy, Electron; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*
D002951:Citrates; D005456:Fluorescent Dyes; D007211:Indoles; D019343:Citric Acid; C048960:indo-1; D002118:Calcium