Physiology and Biophysics

Steven C. Sansom, Ph.D.

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ACADEMIC DEGREES:

Graduate School:       University of Texas Health Science Center
Postdoctoral Training: Yale University School of Medicine

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Contact Name: Steven C. Sansom, Ph.D.
Phone Number: (402) 559-2919
e-mail address: Ssansom@unmc.edu

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• GRANT SUPPORT (last 3 years):

National Institutes of Health, Mechanism of Regulation on a Glomerular K Channel, 07-01-97/06-30-01, Principal Investigator.
National Institutes of Health, Hormonal Influences on the Renal Microvasculature, 07-01-98/06-30-03, Co-Investigator.
American Diabetes Association, Role of Glomerular K+ Channels in Diabetic Hyperfiltration, 07-01-97/06-30-98, Principal Investigator.
Nebraska Kidney Foundation, Electrophysiology of Mesangial Cells in Diabetes Nephropathy, 07-01-98/06-30-99, Principal Investigator.

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• PUBLICATIONS (last 3-5 years):

Stockand, J.D., M. Silverman, D. Hall, T. Derr, B. Kubacak and S.C. Sansom. Arachidonic acid potentiates the feedback response of mesangial BKCa channels to angiotensin II. Am. J. Physiol. Renal Physiol. 274:F658-F664, 1998.

Sansom, S.C., P. Mehta and D. Hall. Potentiating effects of hyperosmolality and epidermal growth factor on the release of arachidonic acid in human glomerular cells. Diabetes Res. & Clin. Pract. 43:21-31, 1999.

Hall, D.A., P.K. Carmines and S.C. Sansom. Dihydropyridine-sensitive Ca2+ channels in human glomerular mesangial cells. Am. J. Physiol. Renal Physiol. 278:F954-F961, 2000.

Ma, R., S. Smith, A. Child, P.K. Carmines and S.C. Sansom. Store-operated Ca2+ channels in human glomerular mesangial cells. Am. J. Physiol. Renal Physiol. 278:F97-F103, 2000.

Sansom, S.C., R. Ma, P.K. Carmines and D. Hall. Role of CAMKII in the regulation of Ca2+-activated K+ channels in contractile cells. Am. J. Physiol. Renal Physiol. 279:F283-F288, 2000.

Ma, R. and S.C. Sansom. Epidermal growth factor activates store-operated calcium channnels in human glomerular mesangial cells. J. Am. Soc. Nephrology, in press, 2001.

Fallet, R.W., J.P. Bast, K. Fujiwara, N. Ishii, S.C. Sansom and P.K. Carmines. Influence of Ca2+-activated K+ channels on rat renal arteriolar responses to depolarizing agonists. Am. J. Physiol. Renal, 280. F583-F591. 2001.

Ma, R., P. Kudlacek, J. Pluznick and S. C. Sansom. Protein kinase C activates store-operated Ca2+ channels in human glomerular mesangial cells.  Journal of Biological Chemistry. 276 (28), 25759-25765, 2001.

Stockand, J.D. and S.C. Sansom. Potassium Channels in the Renal Circulation; in: Cardiovascular Biology, in press, 2000.

Sansom, S.C., S. Muto and G.H. Giebisch. Potassium Homeostasis: Control of Potassium Excretion. In: Textbook of Nephrology, 2^nd Edition, Ed. S. Massry and R. Glassock, Williams & Wilkins, Baltimore, in press, 2000.

Carmines, P.K. and S.C. Sansom. Quick Look Medicine: Renal System, Fence Creek Publishing, LLC., in press, 2001.

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• PREVIOUS GRADUATE STUDENTS/POST-DOCTORAL FELLOWS (present location):

James Stockand, 1992-1996, Ph.D. Assistant Professor of Physiology, University of Texas Medical School at San Antonio
Meredith Silverman, 1995-1996, Masters Candidate

Research Fellows:
Shuichi Ono, M.D., 1993-1995
Macaulay Onuigi, M.D., 1994-1996
Rong Ma, Ph.D., 1999-present Department of Physiology, UNMC
Patrick Kudlacek, 2000-present Department of Physiology, UNMC

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• CURRENT RESEARCH PROJECTS:

Mesangial cells are smooth muscle-like contractile cells that control glomerular filtration rate (GFR) by regulating the capillary filtration surface area. In late stages of diabetes mellitus, MC expand and proliferate, leading to occlusion of the filtering capillaries and decrease in GFR. In general, our laboratory is interested in how ion selective channels regulate contractile tone and growth of mesangial cells. Currently, we have two major projects addressing these issues. The first project involves determining how vasorelaxants such as nitric oxide (NO) and atrial natriuretic peptide (ANP) regulate K channels of MC at the molecular level. In this project, we are finding that vasorelaxants activate a specific type of K channel through a cyclic GMP kinase pathway. We are studying the molecular details of this phosphorylation mechanisms and its physiological relevance to the regulation of GFR during normal conditions and during high salt intake. These studies could explain how or why some populations are more genetically prone to hypertension. In the 2^nd project, we are studying the role of store-operated Ca channels (SOC) in the control of mesangial cell growth and expansion. Our studies show that SOC, normally used as the pathways for CA cell entry after depletion of intracellular stores of Ca, may be involved in the growth of MC in response to the conditions of glomerular injury in the late stages of diabetes mellitus. Our lab utilizes patch clamp techniques, molecular methods, confocal microscopy and fura-2 fluorescent measurements of intracellular Ca concentration to study these issues.

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• SPECIALIZED LABORATORY/CLINICAL RESEARCH RESOURCES:

Patch-clamp technology

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