Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.
Biochem Biophys Res Commun. 2012 Jan 6;417(1):607-12. doi: 10.1016/j.bbrc.2011.12.015. Epub 2011 Dec 11.
It was recently demonstrated that laser irradiation can control the beating of cardiomyocytes and hearts, however, the precise mechanism remains to be clarified. Among the effects induced by laser irradiation on biological tissues, temperature change is one possible effect which can alter physiological functions. Therefore, we investigated the mechanism by which heat pulses, produced by infra-red laser light under an optical microscope, induce contractions of cardiomyocytes. Here we show that microscopic heat pulses induce contraction of rat adult cardiomyocytes. The temperature increase, ΔT, required for inducing contraction of cardiomyocytes was dependent upon the ambient temperature; that is, ΔT at physiological temperature was lower than that at room temperature. Ca(2+) transients, which are usually coupled to contraction, were not detected. We confirmed that the contractions of skinned cardiomyocytes were induced by the heat pulses even in free Ca(2+) solution. This heat pulse-induced Ca(2+)-decoupled contraction technique has the potential to stimulate heart and skeletal muscles in a manner different from the conventional electrical stimulations.
最近的研究表明，激光照射可以控制心肌细胞和心脏的跳动，但具体的机制仍有待阐明。在激光照射对生物组织产生的各种影响中，温度变化是一种可能的影响因素，它可以改变生理功能。因此，我们研究了红外激光在光学显微镜下产生的热脉冲是如何引起心肌细胞收缩的。我们发现，微观热脉冲可以引起成年大鼠心肌细胞的收缩。引起心肌细胞收缩所需的温度升高（ΔT）取决于环境温度；也就是说，生理温度下的ΔT 低于室温下的ΔT。通常与收缩相关的 Ca(2+)瞬变没有被检测到。我们证实，即使在游离 Ca(2+)溶液中，热脉冲也能引起去神经化心肌细胞的收缩。这种热脉冲诱导的 Ca(2+)解偶联收缩技术有可能以不同于传统电刺激的方式刺激心脏和骨骼肌。
