Coronary ion channels, gender and vasoreactivity

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DESCRIPTION (provided by applicant): My long-term professional goal is to continue to strive for both academic and research excellence in the field of adaptive coronary physiology with a focus on understanding the role of ion channels in regulating coronary vasoreactivity and phenotypic modulation during health and disease. My goal is to develop a truly "vertical" approach to research, from the level of gene expression to translational approaches using in vivo clinical measures to pursue novel hypotheses. The proposed research career award will be instrumental in achieving this integrative approach by offering the opportunity to focus the time, energy and resources to develop and refine the spectrum of techniques necessary for this integrative approach. The University of Missouri and the Dalton Cardiovascular Research Center provide a truly unique environment to achieve these goals. Much of the proposed research will focus on sex hormone effects on the coronary vasculature, especially at the cellular/molecular level. Sex hormones exert profound influence on vascular smooth muscle physiology, including proliferation, ion channel activity and channel expression. Coronary smooth muscle (CSM) ion channel activity is central to both regulation of coronary blood flow and the progression of vascular disease. We have demonstrated that CSM calcium and potassium channel activity are strongly influenced by gender. This study will determine the mechanism for gender-specific differences in CSM voltage-gated calcium (VGCC) and K channel activity and the consequent effects on intracellular calcium ([Cai]) regulation and vasoreactivity. The overall hypothesis is that coronary arterial reactivity in males is greater due to a testosterone (TST)-dependent increase in VGCC synthesis and an enhanced propensity for coronary vasospasm (CVS). Both in vivo (intact, gonadectomized and hormone-replaced swine) and in vitro techniques will be used to determine the role of gender, TST and estrogen (E2) in regulating CSM ion channel activity and coronary arterial reactivity. A model of coronary vasospasm will be used to assess the role of sex-specific differences in VGCC activity on the progression and severity of vascular disease. The goal of this research is to determine gender-related cellular and molecular differences in CSM as they relate to gender differences in propensity for coronary disease.