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Endothelium‐dependent frequency modulation of Ca 2+ signalling in individual vascular smooth muscle cells of the rat
Author(s) -
Kasai Yasuyo,
Yamazawa Toshiko,
Sakurai Takashi,
Taketani Yuji,
Iino Masamitsu
Publication year - 1997
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1997.349be.x
Subject(s) - vascular smooth muscle , acetylcholine , stimulation , inhibitory postsynaptic potential , endothelium , chemistry , myocyte , intracellular , medicine , endocrinology , microbiology and biotechnology , biology , biophysics , smooth muscle
1 We visualized intracellular Ca 2+ concentration ([Ca 2+ ] i ) changes, using fluo‐3 as an indicator, of individual vascular smooth muscle cells and endothelial cells within intact rat tail arteries by confocal microscopy. 2 Using a piezo‐driven objective, we focused on endothelial and smooth muscle cell layers alternately to obtain Ca 2+ images of their cells. In the presence of 1 μ m acetylcholine (ACh), individual endothelial cells responded with intermittent increases in the [Ca 2+ ] i (Ca 2+ oscillations). At the same time, the frequency of Ca 2+ oscillations in smooth muscle cells induced by electrical stimulation of the perivascular sympathetic nerve was greatly decreased. 3 A [Ca 2+ ] i rise during the oscillations in the endothelial cells propagated in the form of a wave along the long axis of the cells. 4 In the presence of a NO synthase inhibitor, no significant inhibitory effect of ACh on the Ca 2+ signalling in the vascular smooth muscle cells was detected, although the Ca 2+ oscillations in the endothelial cells persisted. 5 The inhibitory effect of ACh on the frequency of Ca 2+ oscillations in the vascular smooth muscle cells was mimicked by 1 μ m sodium nitroprusside, a NO donor. 6 These results indicate that Ca 2+ waves and oscillations in vascular endothelial cells regulate NO production, which modulates vascular tone by decreasing the frequency of Ca 2+ oscillations in smooth muscle cells activated by sympathetic agonists.