Rhythm-dependent role of different calcium stores in cardiac muscle: X-ray microanalysis

• Published in: Journal of molecular and cellular cardiology Vol. 14; no. 8; pp. 487 - 492
• Main Authors: Wendt-Gallitelli, Maria Fiora, Jacob, Ruthard
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.1982
• Subjects: Animals; Calcium - metabolism; Calcium quantification; Electron Probe Microanalysis; Guinea Pigs; In Vitro Techniques; Myocardial Contraction; Paired stimulation; Papillary Muscles - physiology; Rested state contraction; Rested state contraction; Paired stimulation; Calcium quantification
• ISSN: 0022-2828; 1095-8584
• DOI: 10.1016/0022-2828(82)90157-2

Under extremely different stimulation patterns such as paired-pulse stimulation, or stimulation after prolonged rest, papillary muscles of guinea-pig show differences in contraction. An early high contraction (360 ms to peak tension) results from paired stimulation at short basic stimulus interval, whereas a small “late” contraction normally occurs (550 ms to peak tension) at a stimulus interval of several minutes (rested state contraction) [Figure 1(a)]. The marked differences in the rate of rise and time to peak of tension in the two cases suggest that different calcium stores releasing calcium in a different mode could be responsible for the different pattern of contraction [ 1, 7]. We have examined this question by looking for calcium stores involved in such states of contraction with the aid of crytotechniques and electron probe microanalysis of chemically untreated shock frozen preparations of guinea-pig papillary muscle.