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Fast calcium responses along endothelium of arteriolar networks during blood flow
Author(s) -
Bagher Pooneh,
Davis Michael J.,
Segal Steven S.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.948.18
Subject(s) - arteriole , calcium , cremaster muscle , blood flow , endothelium , chemistry , microcirculation , anatomy , biophysics , vasodilation , venule , pipette , medicine , endocrinology , biology , organic chemistry
To study endothelium‐specific calcium signaling in vivo we utilized the superfused (pH 7.4; 34 °C) cremaster muscle preparation in anesthetized male transgenic mice expressing the calcium sensor GCaMP2 under endogenous transcriptional regulation of connexin40 (Cx40). Endothelial calcium waves have been characterized as a transient fluorescence increase initiated by ACh that travels bidirectionally along arterioles at 116 µm/s and decays within 1 mm. Here we report a novel "fast calcium response (FCR)" that travels at mm/s along arteriolar networks in the direction of convection during blood flow. To determine whether FCR was blood flow‐dependent, an arteriole (diameter, 30‐50 µm) was occluded upstream or downstream from the site of abluminal ACh microiontophoresis (1 µm pipette tip; 500 ms, 500 nA). The FCR was eliminated when blood flow ceased (n=4), whereas removing the occluder restored the FCR along with blood flow. Redirecting flow into a side branch also redirected the FCR. These findings demonstrate that focal release of a vasoactive substance adjacent to an arteriole can activate entire networks of arteriolar endothelial cells through gaining access to the flow stream. Support: NIH HL041026 , AR048523.