![]() |
|
|
H Xie, I Laher and JA Bevan
Department of Pharmacology, College of Medicine, University of Vermont, burlington, USA.
The objective of this study was to determine whether protein kinase C (PKC) activation is involved, and what its role might be, in flow- induced contraction. Contractions induced by flow (40 microliters/min), K+ (25 mM) and histamine (300 nM) in segments of the rabbit fatal vein were compared under isometric conditions. The PKC activator 12-O- tetradecanoylphorbol-13-acetate (50 nM) significantly enhanced flow- induced and K(+)-induced, but not histamine-induced, contractions. Down- regulation of PKC by preincubation with phorbol 1,13-dibutyrate (10 nM for 24 hr) markedly inhibited flow contraction. Although histamine- induced contraction was also affected, the response to K+ remained unchanged. The potentiation of flow-induced contraction by 12-O- tetradecanoylphorbol-13-acetate was prevented by the voltage-gated Ca+2 channel antagonist diltiazem (1 microM). When the PKC activator 12-O- tetradecanoylphorbol-13-acetate (50 nM) was added in a Ca(+2)-free medium containing manganese (1 mM), flow-induced and 25 mM K(+)-induced contractions were enhanced and unaltered, respectively, but histamine- induced contraction was reduced. It is argued that of three types of contractions studied, PKC predominantly modulates flow-induced contraction. PKC can influence this contraction through increases in both Ca++ entry and Ca++ sensitivity.
This article has been cited by other articles:
![]() |
D. Perlegas, H. Xie, S. Sinha, A. V. Somlyo, and G. K. Owens ANG II type 2 receptor regulates smooth muscle growth and force generation in late fetal mouse development Am J Physiol Heart Circ Physiol, January 1, 2005; 288(1): H96 - H102. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. A. Madden and N. J. T. Christman Integrin signaling, free radicals, and tyrosine kinase mediate flow constriction in isolated cerebral arteries Am J Physiol Heart Circ Physiol, December 1, 1999; 277(6): H2264 - H2271. [Abstract] [Full Text] [PDF] |
||||