Relationship between asynchronous Ca2+ waves and force development in intact smooth muscle bundles of the porcine trachea.
نویسندگان
چکیده
Fluctuations in intracellular calcium concentration ([Ca2+]i) constitute the main link in excitation-contraction coupling (E-C coupling) in airway smooth muscle cells (ASMC). It has recently been reported that ACh induces asynchronous recurring Ca2+ waves in intact ASMC of murine bronchioles. With the use of a novel technique allowing us to simultaneously measure subcellular [Ca2+]i and force generation in ASMC located within an intact tracheal muscle bundle, we examined a similar pattern of Ca2+ signaling in the trachea. We found that application of ACh resulted in the generation of recurring intracellular Ca2+ waves progressing along the longitudinal axis of the ribbon-shaped intact ASMC. These Ca2+ waves were not synchronized between neighboring cells, and induction of wave-like [Ca2+]i oscillations was temporally associated with development of force by the tracheal muscle bundle. By comparing the concentration dependence of force generation and the parameters characterizing the [Ca2+]i oscillations, we found that the concentration-dependent increase in ACh-induced force development by the tracheal smooth muscle bundle is achieved by differential recruitment of intact ASMC to initiate Ca2+ waves and by enhancement in the frequency of [Ca2+]i oscillations and elevation of interspike [Ca2+]i once the cells are recruited. Our findings demonstrate that asynchronous recurring Ca2+ waves underlie E-C coupling in ACh-induced contraction of the intact tracheal smooth muscle bundle. Furthermore, in contrast to what was reported in enzymatically dissociated ASMC, Ca2+ influx through the L-type voltage-gated Ca2+ channel was not an obligatory requirement for the generation of [Ca2+]i oscillations and development of force in ACh-stimulated intact ASMC.
منابع مشابه
The relationship between asynchronous Ca waves and force development in intact smooth muscle bundles of the porcine trachea
Fluctuations in intracellular calcium ion concentration ([Ca]i) constitute the main link in excitation-contraction coupling in the airway smooth muscle cells (ASMC). It has been recently reported that acetylcholine induces asynchronous recurring Ca waves in the intact ASMC of murine bronchioles. Using a novel technique that allows us to simultaneously measure sub-cellular [Ca]i and force genera...
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عنوان ژورنال:
- American journal of physiology. Lung cellular and molecular physiology
دوره 285 6 شماره
صفحات -
تاریخ انتشار 2003