In:
FEBS Letters, Wiley, Vol. 440, No. 1-2 ( 1998-11-27), p. 183-187
Abstract:
The effects of the Rho‐kinase inhibitor, Y‐27632 [1] on Ca 2+ ‐sensitization of force induced by arachidonic acid (AA), phorbol 12,13‐dibutyrate (PDBu), GTPγS, and by the stable thromboxane analog, 9,11‐dideoxy‐9α,11α‐methanoepoxy‐PGF 2α (U‐46619), were determined in α‐toxin‐permeabilized smooth muscles. Y‐27632 relaxed (up to 99%) Ca 2+ ‐sensitization by GTPγS (10 μM) and U‐46619 (1 μM), but not by PDBu (20 μM), and reduced GTPγS‐induced myosin light chain (MLC 20 ) phosphorylation from 28% to 17% ( P =0.002). GTPγS‐induced force sensitization was inhibited by Y‐27632 more potently when the inhibitor was added during the plateau of force than prior to stimulation. In α‐toxin‐permeabilized smooth muscle, Y‐27632 inhibited AA (50 μM)‐induced Ca 2+ ‐sensitization of force (by 66±1.3%) and reduced MLC 20 phosphorylation. In contrast, Y‐27632 did not relax force Ca 2+ ‐sensitized by AA in smooth muscle permeabilized with Triton X‐100. We conclude that (i) AA induces Ca 2+ ‐sensitization through dual mechanisms, one mediated by Rho‐kinase (or a related kinase), and (ii) Rho‐kinase is not required for phorbol ester‐induced Ca 2+ ‐sensitization.
Type of Medium:
Online Resource
ISSN:
0014-5793
,
1873-3468
DOI:
10.1016/S0014-5793(98)01455-0
Language:
English
Publisher:
Wiley
Publication Date:
1998
detail.hit.zdb_id:
1460391-3
SSG:
12
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