Calcium waves in skinned cardiac myocytes evoked by two-photon excitation photolysis of caged calcium.
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',N'-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 microM), 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.
Department of Physiology, Tokyo Medical University, Tokyo, 160-8402 Japan.
M
M
Konishi
T
T
Yamashita
S
S
Nakayama
S
S
Kokubun
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000493:pharmacokinetics; D004594:Electrophysiology; D006352:Heart Ventricles / Q000166:cytology*; D008297:Male; D018613:Microscopy, Confocal; D055095:Optics and Photonics; D018408:Patch-Clamp Techniques; D010539:Permeability; D010782:Photolysis; D051381:Rats; D017208:Rats, Wistar; D012503:Saponins / Q000008:administration & dosage; D016276:Ventricular Function
D012503:Saponins; D002118:Calcium