title: Ultrafast Ca2+ wave in cultured vascular smooth muscle cells aligned on a micropatterned surface.
abstract: Communication between vascular smooth muscle cells (SMCs) allows control of their contraction and so regulation of blood flow. The contractile state of SMCs is regulated by cytosolic Ca2+ concentration ([Ca2+]i) which propagates as Ca2+ waves over a significant distance along the vessel. We have characterized an intercellular ultrafast Ca2+ wave observed in cultured A7r5 cell line and in primary cultured SMCs (pSMCs) from rat mesenteric arteries. This wave, induced by local mechanical or local KCl stimulation, had a velocity around 15 mm/s. Combining of precise alignment of cells with fast Ca2+ imaging and intracellular membrane potential recording, allowed us to analyze rapid [Ca2+]i dynamics and membrane potential events along the network of cells. The rate of [Ca2+]i increase along the network decreased with distance from the stimulation site. Gap junctions or voltage-operated Ca2+ channels (VOCCs) inhibition suppressed the ultrafast Ca2+ wave. Mechanical stimulation induced a membrane depolarization that propagated and that decayed exponentially with distance. Our results demonstrate that an electrotonic spread of membrane depolarization drives a rapid Ca2+ entry from the external medium through VOCCs, modeled as an ultrafast Ca2+ wave. This wave may trigger and drive slower Ca2+ waves observed ex vivo and in vivo.
authors.affiliation: Laboratory of Cell Biophysics, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Facultad de Ciencias Básicas, Politécnico Colombiano JIC, Medellín, Colombia. Electronic address: jairo.quijano@epfl.ch.
authors.forename: Jairo C
authors.initials: JC
authors.lastname: Quijano
authors.forename: Benoît
authors.initials: B
authors.lastname: Vianay
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Bény
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Meister
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D002478:Cells, Cultured; D017629:Gap Junctions / Q000378:metabolism; D007477:Ions / Q000737:chemistry / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008638:Mesenteric Arteries / Q000166:cytology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D015220:Calcium Channels; D007477:Ions; D011189:Potassium Chloride; D002118:Calcium
keywords: Membrane depolarization; Smooth muscle cells; Ultrafast calcium wave