Regulation of vascular contraction and, thus, vascular resistance is generally associated with the activation of receptors coupled to guanine nucleotide associated proteins (G-proteins). Tyrosine kinase(s), enzymes critically important to vascular smooth muscle cell growth, may participate in the dynamic process of controlling vascular tone; a particularly important tyrosine kinase-dependent pathway is the mitogen activated protein kinase or MAPK pathway. The unifying hypothesis of this project is that G-protein coupled agonists, specifically 5-HT (serotonin, 5-hydroxytryptamine), stimulate vascular tyrosine kinase(s) to produce contraction. This is a novel and undescribed signal transduction pathway for the G-protein coupled agonist 5-HT; importantly, contractility to 5-HT and other agonists is dramatically increased in diseased states with documented vascular growth and remodeling (hypertension, atherosclerosis, restenosis) and contractile response to 5-HT is an excellent marker for vascular disease. Thus, tyrosine kinase(s), as activated by 5-HT, may play a significant role in the altered function of the vasculature in disease. Two specific experimental hypotheses which integrate studies from protein to the whole animal will be addressed: 1) 5-HT activates tyrosine kinase(s), in particular the tyrosine kinase MAPK kinase (MEK), to result in direct vascular smooth muscle contraction and potentiation of vasoconstrictor- induced contraction, 2) 5-HT increases tyrosine kinase activity, as measured by protein tyrosyl-phosphorylation and MEK activity, in vascular smooth muscle cells and arteries. Four experimental approaches will be employed: 1) isolated tissue bath technique to measure vascular contractility; 2) myograph technique to measure resistance vessel contractility; 3) Western analyses of vascular smooth muscle cell lysates and arteries to determine 5-HT-induced changes in protein tyrosyl-phosphorylation, especially that of the substrates of MEK (the MAPKs); 4) MEK activity assays. Based on preliminary results, it is predicted that tyrosine kinases, including MEK, mediate a portion of 5- HT-induced contraction, both direct contraction and that which potentiates responses to other cardiovascular hormones. The results of these experiments will reveal novel mechanisms for 5-HT signal transduction in vascular smooth muscle contraction. The pathways established will set the basis for a novel manner of normal cellular activation by 5-HT and most likely other G-protein coupled agonists, and can thus be an initial step in understanding how signal transduction for 5-HT and other agonists may change in diseased states associated with vascular smooth muscle growth or remodeling.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29HL058489-04
Application #
6389678
Study Section
Experimental Cardiovascular Sciences Study Section (ECS)
Program Officer
Lin, Michael
Project Start
1998-09-01
Project End
2003-08-31
Budget Start
2001-09-01
Budget End
2002-08-31
Support Year
4
Fiscal Year
2001
Total Cost
$109,905
Indirect Cost
Name
Michigan State University
Department
Pharmacology
Type
Schools of Osteopathy
DUNS #
193247145
City
East Lansing
State
MI
Country
United States
Zip Code
48824
Watts, Stephanie W; Davis, Robert Patrick (2011) 5-hydroxtryptamine receptors in systemic hypertension: an arterial focus. Cardiovasc Ther 29:54-67