- 作者: Jason D. Gardner; Joseph N. Benoit
- 作者服務機構: Department of Physiology, Universty of South Alabama, Mobile, Ala., USA
- 中文摘要: --
- 英文摘要: Objective: The purpose of this study was to evaluate thecontribution of capacitative calcium influx to intracellularcalcium levels during agonist-induced stimulation ofvascular smooth muscle cells. Methods: Aortic vascularsmooth muscle cells (A7r5)were loaded with lndo-1 andintracellular calcium transients were measured. Cellswere challenged with either arginine vasopressin (0.5 uM)or thapsigargin (1 uM). Lanthanum (1 mM) was used toblock capacitative calcium influx through store-operatedchannels. Calcium traces were analyzed for basal, peakand plateau responses. Recordings were derivatized andintegrated to gain additional information. Nonlinear re-gression provided a time constant that describes restora-tion of ionic equilibrium involving both sequestration andextrusion pathways. Results: Stimulation of cells withthapsigargin produced a non-L-type calcium influx thatwas attenuated by lanthanum. Cells excited with vaso-pressin exhibited a rapid calcium increase followed by agradual decrease to a plateau level. Lanthanum pretreat-ment prior to stimulation caused no significant change inbaseline, peak or plateau calcium levels as compared tocontrol. Lanthanum caused no significant change inmaximal calcium release rate, calcium integrals or timeconstant as compared to control. Conclusions: Capacita-tive calcium entry can occur in vascular smooth musclecells, but does not appear to contribute significantly tothe vasopressin response.
- 中文關鍵字: --
- 英文關鍵字: --