External ATP induced increase in intracellular free calcium in mammalian atrial myocytes.
Extracellularly applied ATP elicited a transient increase in intracellular free calcium concentration ([Ca2+]i) measured by fura-2 fluorescence digital imaging microscopy in isolated rabbit and guinea-pig atrial myocytes. In the electrophysiological study, ATP induced a transient depolarization of the membrane potential due to activation of a rapidly desensitizing inward current. Our results indicate that in mammalian atrial myocytes, ATP evoked transient increase in [Ca2+]i through release of internally stored Ca2+ associated with inflow of external Ca2+, mainly through L-type Ca channels which were voltage-activated secondarily to ATP-induced conductance changes.
Hirano
Y
Y
Department of Cardiovascular Diseases, Tokyo Medical and Dental University, Japan.
Sawanobori
T
T
Hiraoka
M
M
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004594:Electrophysiology; D016257:Fura-2; D006168:Guinea Pigs; D006325:Heart Atria / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000502:physiology; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D011817:Rabbits; D018048:Receptors, Purinergic P2 / Q000187:drug effects
D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate; D002118:Calcium; D016257:Fura-2