Premium
Regulation of cytosolic calcium by collagen in single human platelets
Author(s) -
Poole Alastair W.,
Watson Stephen P.
Publication year - 1995
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1995.tb16326.x
Subject(s) - platelet , cytosol , calcium , fura 2 , chemistry , tyrosine phosphorylation , biophysics , endocrinology , medicine , microbiology and biotechnology , tyrosine , biochemistry , biology , enzyme
1 There is controversy in the literature as to whether collagen is able to induce directly a rise in cytosolic calcium concentration ([Ca 2+ ] i ) in human platelets. We have addressed this question by observing the cytosolic calcium response of single fura‐2‐loaded human platelets settling onto a collagen‐coated surface using dynamic fluorescence ratio imaging. 2 Following a short lag phase after adherence to collagen fibres, platelets underwent a rapid rise in cytosolic calcium from basal values of 80 ± 13 nM (n = 24) to a peak of 475 ± 42 nM (n = 24) which was sustained for the remaining period of the experiment. 3 The tyrphostin protein tyrosine kinase inhibitor, ST271, reduced substantially the proportion of platelets which exhibited a rise in [Ca 2+ ] i on adherence to collagen and transformed the response in remaining cells to one of oscillations. 4 In contrast, and as a control for collagen, laminin‐coated surfaces induced adherence of human platelets without elevating intracellular [Ca 2+ ]; the cells however remained responsive to ADP. 5 We conclude that collagen directly induces a rise in cytosolic calcium in single human platelets through a tyrosine kinase‐mediated pathway.