Personal HistoryAfter receiving a Ph.D. in Physiology in 1978 from the University of Utah in Salt Lake City, I did post-doctoral work with Dr. John R. Blinks in the Department of Pharmacology at the Mayo Foundation in Rochester, MN. There, we made some of the first measurements of Calcium ion concentration in heart muscle, using the photoprotein, aequorin. I then joined the faculty of the University of Maryland at Baltimore in 1982 where my research has been funded continuously by NIH. In addition to being a ‘calciumologist’, I teach cardiovascular physiology to first-year medical students. I'm on the faculty of the interdepartmental training programs Membrane Biology, and Muscle Biology, and am a member of the University of Maryland Graduate School. I’m also an Adjunct Professor at Xi’an Jiatong University, China.
Research InterestsWe are using high resolution imaging to study the role of Ca2+ in adrenergic control mechanisms in intact, pressurized resistance arteries. Imaging Ca2+ in such a preparation is challenging, compared to single isolated cells. It is expected to be highly rewarding however, because of the ability to see [Ca2+]i during truly physiological stimuli, such as pressure, shear stress, or neuronal stimulation. Furthermore, the cells are connected normally (via gap junctions), allowing the observation of cellular communication or co-ordinated activity that cannot exist in isolated cells. This is most important in view of the emerging concept that arterial function is carried out by 'information networks within the arterial wall' (Beny, 1999). While the potential benefits of such preparations are undeniable, the difficulty in imaging Ca2+ in such preparations is that they are thick, scatter light and can move. Nevertheless, our preliminary data shows that with modern optical sectioning techniques (confocal and two-photon) it is possible to observe events within subcellular volumes within part of a much larger scene, comprised of a group of inter-connected cells. In the case of an artery, such a scene can encompass several vascular smooth muscle cells, nerve endings and endothelial cells. Recently, we have been concerned with the mechanisms governing release of the sympathetic neurotransmitters, NE and ATP from sympathetic nerve endings in these arteries. ATP binds to P2X1 receptors to activate inward Ca2+ current and produce a local, non-propagating post-junctional Ca2+ transient that we called a 'jCaT' (junctional Ca Transient). NE binds to a1-adrenoceptors to produce propagating Ca2+ waves. These studies are providing a new picture of Ca2+ signaling in the smooth muscle of arteries. In summary, by obtaining high resolution images of molecular messengers within the walls of intact pressurized arteries, it is hoped that a new, more integrated view of the cellular and inter-cellular mechanisms that control vascular resistance can be obtained.
- Christine Lamont, Ph.D. - Research Associate
- Albert Y. Rhee, Ph.D. - Post-Doctoral Fellow
- Joseph Zacharia, Ph.D. - Post-Doctoral Fellow
- Manxiang Li, M.D. - Post-Doctoral Fellow
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