Spatial and Temporal Inhomogeneities During Ca2+ Release From the Sarcoplasmic Reticulum in Pig Ventricular Myocytes

ABSTRACT—The [Ca]i transient of ventricular myocytes during normal excitation-contraction coupling is the summation of primary Ca release events, which originate at the junction of the sarcoplasmic reticulum (SR) and the T-tubular system. Studies in small mammals have shown a high density of release...

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Bibliographic Details
Published in:Circulation research 2002-11, Vol.91 (11), p.1023-1030
Main Authors: Heinzel, Frank R, Bito, Virginie, Volders, Paul G.A, Antoons, Gudrun, Mubagwa, Kanigula, Sipido, Karin R
Format: Article
Language:English
Subjects:
Adrenergic beta-Agonists - pharmacology
Animals
Biological and medical sciences
Caffeine - pharmacology
Calcium - metabolism
Calcium Channel Agonists - pharmacology
Calcium Signaling - physiology
Cell Separation
Electric Stimulation
Fundamental and applied biological sciences. Psychology
Heart
Heart Ventricles - cytology
Heart Ventricles - drug effects
Heart Ventricles - metabolism
In Vitro Techniques
Isoproterenol - pharmacology
Mice
Myocardial Contraction - physiology
Myocardium - cytology
Myocardium - metabolism
Patch-Clamp Techniques
Ryanodine Receptor Calcium Release Channel - drug effects
Ryanodine Receptor Calcium Release Channel - metabolism
Sarcoplasmic Reticulum - metabolism
Swine
Vertebrates: cardiovascular system
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Summary:ABSTRACT—The [Ca]i transient of ventricular myocytes during normal excitation-contraction coupling is the summation of primary Ca release events, which originate at the junction of the sarcoplasmic reticulum (SR) and the T-tubular system. Studies in small mammals have shown a high density of release sites, but little is known of larger mammals. We have studied the spatial distribution of SR Ca release in pig ventricular myocytes using a confocal microscopy. In 69 of 107 cells, large inhomogeneities of Ca release were observed along the longitudinal scan line. Areas where the increase of [Ca]i was delayed (time to 50% of peak F/F0 [where F indicates fluorescence intensity, and F0 indicates F at rest] was 26±1 ms in delayed areas versus 11±2 ms in early areas) and smaller (peak F/F0 was 2.27±0.10 for delayed areas versus 2.69±0.13 for early areas; n=13 cells, P
ISSN:0009-7330
1524-4571
DOI:10.1161/01.RES.0000045940.67060.DD