TMB-8 and dibucaine induce tyrosine phosphorylation and dephosphorylation of a common set of proteins in platelets
A. Oda, B. J. Druker, H. Ariyoshi, M. Smith and E. W. Salzman Department of Surgery, Beth Israel Hospital, Harvard Medical School, Boston, Massachusetts 02215, USA. Dibucaine and 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate (TMB-8), which are local anesthetics, affect diverse functions of many...
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Veröffentlicht in: | American Journal of Physiology: Cell Physiology 1995-07, Vol.269 (1), p.C118-C125 |
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Zusammenfassung: | A. Oda, B. J. Druker, H. Ariyoshi, M. Smith and E. W. Salzman
Department of Surgery, Beth Israel Hospital, Harvard Medical School, Boston, Massachusetts 02215, USA.
Dibucaine and 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate (TMB-8),
which are local anesthetics, affect diverse functions of many cell types.
For example, platelet aggregation is inhibited by both, and both cause
changes in platelet morphology and structure. Little is known of the
mechanisms. We found that both dibucaine (0.125-0.5 mM) and TMB-8 (0.25-1.0
mM) induced rapid tyrosine phosphorylation of several platelet proteins
(160, 70-75, and 40 kDa) and dephosphorylation of a 62- to 64-kDa protein
detectable by a specific antiphosphotyrosine monoclonal antibody (4G10).
Platelet aggregation induced by alpha-thrombin (10 nM) was inhibited by the
local anesthetics in approximately the same dose range. Neither dibucaine
nor TMB-8 induced activation of protein kinase C (PKC) or myosin
light-chain kinase. Their activation was not essential for tyrosine
phosphorylation induced by local anesthetics. However, an increase in
tyrosine phosphorylation of several proteins (95-130 kDa) induced by
alpha-thrombin (10 nM) was inhibited by dibucaine (0.5 mM) or TMB-8 (0.5
mM). Furthermore, when dibucaine (0.5 mM) was added 1 min after addition of
alpha-thrombin (10 nM), disaggregation was paralleled to dephosphorylation
of many proteins, including those mentioned. Tyrosine phosphorylation and
dephosphorylation of specific proteins may account for some of the diverse
effects of local anesthetics on platelets and other cells. Addition of
TMB-8 (0.5 mM) or dibucaine (0.5 mM) also inhibited activation of PKC,
induced by alpha-thrombin (10nM), suggesting that some of the inhibitory
effects of dibucaine or TMB-8 may be due to inhibitory effects of local
anesthetics on PKC. |
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ISSN: | 0363-6143 0002-9513 1522-1563 |
DOI: | 10.1152/ajpcell.1995.269.1.C118 |