[Role of intracellular calcium stores in the generation of phasic component of K-contraction of the frog myocardium].
Treatment of the frog heart ventricle strip with 24 mM caffeine under condition of repetitive stimulation increases the amplitude of and decelerates relaxation of the phasic component of potassium contraction (100 mM KCl), as well as prevents the phasic component suppression due to 15-min application of Ca-channels blocking agent D-600 (4 X 10(-5) g/ml) or to a long-lasting (15-20 min) inactivity of the preparation. Adrenaline inhibits the phasic component and accelerates its relaxation. Ca++ ions which trigger the phasic component of the K-contraction seems to enter the myoplasm at the onset of membrane depolarization not from the sarcoplasmic reticulum but from some other pools, probably from the hypothetic voltage-dependent caffeine-insensitive submembrane Ca-stores.
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D003470:Culture Media; D004347:Drug Interactions; D004558:Electric Stimulation; D004837:Epinephrine / Q000494:pharmacology; D005711:Gallopamil; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000502:physiology*; D009200:Myocardial Contraction; D009206:Myocardium / Q000648:ultrastructure*; D011188:Potassium / Q000502:physiology*; D011896:Rana temporaria
D003470:Culture Media; D005711:Gallopamil; D002110:Caffeine; D011188:Potassium; D002118:Calcium; D004837:Epinephrine
Issledovanie roli vnutrikletochnykh Ca-depo v geneze fazicheskoĭ komponenty kalievoĭ kontraktury miokarda liagushki.