1. Archive
2. Vol.51, No.1

Calcium Waves in Skinned Cardiac Myocytes Evoked by Two-Photon Excitation Photolysis of Caged Calcium

Abstract: In rat ventricular myocytes chemically skinned with saponin, a local rise of [Ca²⁺] was achieved by two-photon excitation photolysis (TPP) of the caged Ca²⁺ compound 1-(2-nitro-4,5-dimethoxyphenyl)-N,N,N′9,N′9-tetrakis[(oxycarbonyl)methyl]-1,2-ethanediamine (DM-nitrophen). Confocal Ca²⁺ images, by use of fluo-3, were simultaneously collected. TPP of DM-nitrophen induced Ca²⁺ waves propagating over the myocyte, and the local rise of [Ca²⁺] at the site of photolysis sustained for 50–60 ms. These TPP-induced Ca²⁺ events were completely suppressed by ryanodine (10 M), suggesting that Ca²⁺ release resulting from TPP of DM-nitrophen triggered regenerative Ca²⁺ release from the neighboring sarcoplasmic reticulum. The present techniques should be useful to investigate the interaction of elementary Ca²⁺ events, the process leading to global Ca²⁺ movements, in cardiac myocytes and other types of cells.

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