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Two‐photon microscopy enables non‐invasive, in vivo, longitudinal study of arterial Ca 2+ and diameter in optical biosensor mice during the development of hypertension (856.7)
Author(s) -
Mauban Joseph,
Fairfax Seth,
Zhang Jin,
Rizzo Mark,
Wier W.
Publication year - 2014
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.28.1_supplement.856.7
Subject(s) - in vivo , vasomotion , myosin light chain kinase , biosensor , chemistry , medicine , two photon excitation microscopy , endocrinology , artery , phenylephrine , blood pressure , intracellular , ex vivo , biophysics , myosin , vasodilation , biology , in vitro , biochemistry , fluorescence , physics , microbiology and biotechnology , quantum mechanics
Here, we report that use of two‐photon microscopy of ear arteries in exMLCK biosensor mice enables non‐invasive, in vivo, serial examination of vascular smooth muscle Ca 2+ during the development of hypertension. ExMLCK mice express a FRET‐type biosensor of Ca 2+ /Calmodulin based on smooth muscle myosin light chain kinase (MLCK) and its ratiometric properties permit direct quantification of intracellular Ca 2+ concentration. Anesthetized biosensor mice were positioned on a custom platform, facilitating imaging of selected arterial branches within the intact depilated ear, and studied before and during chronic infusion of angiotensin‐II (ANGII; 800 µg/g/day) via mini‐osmotic pump. Acute responsiveness to i.p. phenylephrine (PE; 30µg/g) was determined in a separate group of mice equipped with arterial blood pressure radio telemetry. Eight days of chronic ANGII increased intracellular Ca 2+ from 294±47nM to 501±92nM ( P <0.05) and decreased artery diameter by ‐14±2% ( P <0.05). Acute PE induced robust vasomotion and 2‐3 fold oscillations in spatially averaged Ca 2+ . In summary, this new methodology permits for the first time the simultaneous study of Ca 2+ signaling, structural remodeling and vascular reactivity in the intact living mouse during hypertension development. Grant Funding Source : Supported by NHLBI RO1091969, RO1HL107654, RO1DK077140, and T32HL072751.