Ionic current and pacemaker activity of the S-A node cells.
1) Five membrane current (if, is, ik, ih, il) were observed in rabbit S-A node cells by the voltage clamp method. 2) The outward current (ik) was carried by k ion, while the inward current (is) was mainly carried by Na ion with some contribution of Ca ion. The inward current activated by hyperpolarization (ih) ws a mixed current system, but participation of Na and Cl ions was found to be existed. 3) Each current was analysed according to the Hodgkin-Huxley type equation. 4) Finally the action potential and pacemaker activity of S-A node were reconstructed. 5) In phase 4 diastolic depolarization, is played the major role, but the assistance of ik ws also important.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D008564:Membrane Potentials; D008954:Models, Biological; D011188:Potassium / Q000378:metabolism; D011690:Purkinje Fibers / Q000502:physiology; D011817:Rabbits; D012849:Sinoatrial Node / Q000166:cytology / Q000502:physiology*; D012964:Sodium / Q000378:metabolism
D007473:Ion Channels; D012964:Sodium; D011188:Potassium; D002118:Calcium