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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, RESULTS. Meshes: Animals, Arteries, Cricetinae, Culture Techniques, Enzyme Activation, Genes, Dominant, Green Fluorescent Proteins, Intracellular Signaling Peptides and Proteins, Luminescent Proteins, Microcirculation, Muscle, Skeletal, Muscle, Smooth, Vascular, Phosphotransferases (Alcohol Group Acceptor), Protein-Serine-Threonine Kinases, Recombinant Fusion Proteins, Signal Transduction, Transfection, Vasoconstriction, Vasomotor System, rho-Associated Kinases, rhoA GTP-Binding Protein.
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Does sphingosine kinase modulate microvascular tone and myogenic responses through activation of RhoA/Rho kinase? Context: RhoA and Rho kinase are important modulators of microvascular tone. We tested whether sphingosine kinase (Sphk1) that generates the endogenous sphingolipid mediator sphingosine-1-phosphate (S1P) is part of a signaling cascade to activate the RhoA/Rho kinase pathway. Using a new transfection model, we report that resting tone and myogenic responses of isolated resistance arteries increased with forced expression of Sphk1 in smooth muscle cells of these arteries. Overexpression of a dominant negative Sphk1 mutant or coexpression of dominant negative mutants of RhoA or Rho kinase together with Sphk1 completely inhibited development of tone and myogenic responses.
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The tone-increasing effects of a Sphk1 overexpression suggest that Sphk1 may play an important role in the control of peripheral resistance. Final Decision: yes