Nonsteady motion in unloaded contractions of single frog cardiac cells

• Published in: Biophysical journal Vol. 48; no. 3; pp. 461 - 465
• Main Authors: Tameyasu, T., Toyoki, T., Sugi, H.
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01.09.1985; Biophysical Society
• Subjects: Animals; Applied sciences; Biological and medical sciences; Calcium - pharmacology; Cell Movement; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Heart; Heart - drug effects; Heart - physiology; Myocardial Contraction - drug effects; Myocardium - cytology; Other techniques and industries; Rana catesbeiana; Space life sciences; Ventricular Function; Vertebrates: cardiovascular system; Heart; Cell organelle; Frog; Electrical stimulus; Amphibia; Electrophysiology; Salientia; Muscle contraction; In vitro; Video recording; Vertebrata; High speed; Circulatory system; Sarcomere; Heart cell
• ISSN: 0006-3495; 1542-0086
• DOI: 10.1016/S0006-3495(85)83801-7

We studied the mode of shortening of enzymatically isolated single frog cardiac cells with a high-speed videosystem to see whether or not shortening is smooth. The segmental shortening of the cell in response to electrical stimulation exhibited a clear pause following the initial shortening over a distance of approximately 11 nm/half-sarcomere. Several preparations showed a second pause following the initial one. Nonsteady motion with a pause lasted usually a few tens of milliseconds. The duration of nonsteady motion was shorter in cells with large velocities of steady shortening following the pause than those with smaller velocities.