Premium
Molecular and electrophysiological characterization of transient receptor potential ion channels in the primary murine megakaryocyte
Author(s) -
Carter Richard N.,
Tolhurst Gwen,
Walmsley Gemma,
VizueteForster Matthieu,
Miller Nigel,
MahautSmith Martyn P.
Publication year - 2006
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2006.113886
Subject(s) - transient receptor potential channel , trpm2 , electrophysiology , trpc1 , microbiology and biotechnology , megakaryocyte , ion channel , chemistry , biophysics , trpm7 , trpc6 , membrane potential , patch clamp , sk channel , biology , receptor , biochemistry , neuroscience , haematopoiesis , stem cell
The molecular identity of platelet Ca 2+ entry pathways is controversial. Furthermore, the extent to which Ca 2+ ‐permeable ion channels are functional in these tiny, anucleate cells is difficult to assess by direct electrophysiological measurements. Recent work has highlighted how the primary megakaryocyte represents a bona fide surrogate for studies of platelet signalling, including patch clamp recordings of ionic conductances. We have now screened for all known members of the transient receptor potential (TRP) family of non‐selective cation channels in murine megakaryocytes following individual selection of these rare marrow cells using glass micropipettes. RT‐PCR detected messages for TRPC6 and TRPC1, which have been reported in platelets and megakaryocytic cell lines, and TRPM1, TRPM2 and TRPM7, which to date have not been demonstrated in cells of megakaryocytic/platelet lineage. Electrophysiological recordings demonstrated the presence of functional TRPM7, a constitutively active cation channel sensitive to intracellular Mg 2+ , and TRPM2, an ADP‐ribose‐dependent cation channel activated by oxidative stress. In addition, the electrophysiological and pharmacological properties of the non‐selective cation channels stimulated by the physiological agonist ADP are consistent with a major role for TRPC6 in this G‐protein‐coupled receptor‐dependent Ca 2+ influx pathway. This study defines for the first time the principal TRP channels within the primary megakaryocyte, which represent candidates for Ca 2+ influx pathways activated by a diverse range of stimuli in the platelet and megakaryocyte.