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Title: High-frequency sarcomeric auto-oscillations induced by heating in living neonatal cardiomyocytes of the rat

Highlights: • We tested the effects of infra-red laser irradiation on cardiac sarcomere dynamics. • A rise in temperature (>∼38 °C) induced high-frequency sarcomeric auto-oscillations. • These oscillations occurred with and without blockade of intracellular Ca{sup 2+} stores. • Cardiac sarcomeres can play a role as a temperature-dependent rhythm generator. - Abstract: In the present study, we investigated the effects of infra-red laser irradiation on sarcomere dynamics in living neonatal cardiomyocytes of the rat. A rapid increase in temperature to >∼38 °C induced [Ca{sup 2+}]{sub i}-independent high-frequency (∼5–10 Hz) sarcomeric auto-oscillations (Hyperthermal Sarcomeric Oscillations; HSOs). In myocytes with the intact sarcoplasmic reticular functions, HSOs coexisted with [Ca{sup 2+}]{sub i}-dependent spontaneous beating in the same sarcomeres, with markedly varying frequencies (∼10 and ∼1 Hz for the former and latter, respectively). HSOs likewise occurred following blockade of the sarcoplasmic reticular functions, with the amplitude becoming larger and the frequency lower in a time-dependent manner. The present findings suggest that in the mammalian heart, sarcomeres spontaneously oscillate at higher frequencies than the sinus rhythm at temperatures slightly above the physiologically relevant levels.
Authors:
;  [1] ;  [2] ;  [1] ;  [3]
  1. Department of Pure and Applied Physics, School of Advanced Science and Engineering, Waseda University, Tokyo (Japan)
  2. Department of Cell Physiology, The Jikei University School of Medicine, Tokyo (Japan)
  3. (WABIOS) (Singapore)
Publication Date:
OSTI Identifier:
22458466
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 457; Journal Issue: 2; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; BIOMEDICAL RADIOGRAPHY; CALCIUM IONS; CONCENTRATION RATIO; FLUORESCENCE; HEART; HEATING; LASER RADIATION; LENGTH; OSCILLATIONS; RATS; SARCOPLASMIC RETICULUM; TEMPERATURE DEPENDENCE; TIME DEPENDENCE