Stretching increases calcium influx and efflux in cultured pulmonary arterial smooth muscle cells.
To determine the effect of a single static stretch on calcium fluxes in cultured pulmonary arterial smooth muscle cells (PASMC), calcium influx and efflux were evaluated in PASMC on a collagen-coated silicone membrane using 45Ca2+ as a tracer. A single 20% linear stretch of the silicone membrane of 1 min in duration increased calcium uptake by 71%. This effect was partially inhibited by verapamil or gadolinium, but was not altered by staurosporine, pertussis toxin, or removal of extracellular sodium. Stretch-stimulated calcium uptake attenuated over time, such that uptake during the last minute of a 5-min sustained stretch was 46% of that during the first minute of stretch. A single 20% stretch sustained for 6 min caused a 47% increase in calcium efflux, the magnitude of which was linearly related to the degree of cell stretch. Gadolinium and removal of extracellular calcium each partially inhibited stretch-induced calcium efflux. We conclude that a single static stretch of PASMC causes increases in both calcium influx and efflux. Stretch-stimulated calcium influx does not require sodium influx and is mediated in part by a pathway sensitive to both gadolinium and verapamil. Stretch-stimulated calcium efflux is due to both calcium influx via a gadolinium-sensitive pathway and mobilization of intracellular stores. Because calcium is a key cellular second messenger, these effects of stretch on cellular calcium handling may play a role in the regulation of vascular smooth muscle cell phenotype and function.
Bialecki
R A
RA
Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts.
Kulik
T J
TJ
Colucci
W S
WS
D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D005682:Gadolinium / Q000494:pharmacology; D007700:Kinetics; D009130:Muscle, Smooth / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D037342:Pertussis Toxin; D011651:Pulmonary Artery / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D019311:Staurosporine; D013314:Stress, Mechanical; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000470:Alkaloids; D002121:Calcium Channel Blockers; D010566:Virulence Factors, Bordetella; D005682:Gadolinium; D037342:Pertussis Toxin; D019311:Staurosporine; D002118:Calcium