Thrombin-induced calcium oscillation in human platelets and MEG-01, a megakaryoblastic leukemia cell line.
Digital imaging microscopy revealed that human platelets show periodic intracellular Ca++ elevation in response to 0.01 U/ml thrombin. MEG-01, a megakaryoblastic leukemia cell line, also responded with oscillatory intracellular Ca++ elevation (0.7-1 times/min) to thrombin (0.001-0.003U/ml). Ca++ transients appears to be fused with higher thrombin doses. With extracellular Ca++ concentrations of 0.1 mM or less, Ca++ oscillation could not be elicited, or even when present, it disappeared after a few spikings of [Ca++]i. Extracellular Ca++ concentrations of 0.3 mM or more were required to facilitate ongoing Ca++ oscillation, suggesting an important role of Ca++ influx for Ca++ oscillation.
Ozaki
Y
Y
Department of Clinical and Laboratory Medicine, Yamanashi Medical College, Japan.
Yatomi
Y
Y
Wakasugi
S
S
Shirasawa
Y
Y
Saito
H
H
Kume
S
S
D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007947:Leukemia, Megakaryoblastic, Acute / Q000378:metabolism*; D015219:Substrate Cycling; D013917:Thrombin / Q000494:pharmacology*; D013997:Time Factors; D014407:Tumor Cells, Cultured
D013917:Thrombin; D002118:Calcium