U of M - Dept. of Physiology

Research in my laboratory is directed towards gaining an integrative understanding of the role of the central nervous system in the long-term regulation of arterial pressure and the pathogenesis of hypertension. At the present time we are investigating how circulating hormones, such as angiotensin II and aldosterone, are monitored by specialized sites within the brain called circumventricular organs. We are investigating how these regions influence ongoing sympathetic nerve discharge and ultimately the regulation of arterial pressure. Our long-term goal is to understand, in a quantitative way, the role of such hormonal-sympathetic interactions in normal physiology and the pathophysiology of hypertension. Specifically, we are studying how such interactions are influenced by alterations in dietary salt in hopes of understanding the neurogenic basis of salt-dependent hypertension. A variety of experimental approaches are employed to address these issues including state-of-the-art long-term monitoring of cardiovascular hemodynamics and application of cellular/molecular neurobiological techniques. We have also initiated a collaborative project with the Department of Mathematics to begin developing new mathematical models of how the nervous system regulates cardiovascular function over long periods of time.

In addition to the work in my own laboratory, I am the coordinator for a newly formed national research effort to study the role of the brain in cardiovascular diseases. “The Neurogenic Cardiovascular Diseases Consortium” is a novel NIH funded project which joins 5 major research Universities to investigate neurogenic cardiovascular diseases at all levels of regulation; gene, single cell, neural networks and whole animal. This work will be carried out by Universities of Minnesota (home institution), Pittsburgh, Texas-San Antonio, Florida-Gainesville and Michigan State University.

Selected Publications

Osborn, J.W. and B.J. Hornfeldt Arterial baroreceptor denervation impairs long- term control of arterial pressure during dietary salt loading Am. J. Physiol. 275:H1558-H1566, 1998.

Carlson, S.H., Collister, J.P. and J.W. Osborn. The area postrema modulates hypothalamic Fos responses to intragastric hypertonic saline in conscious rats. Am.J.Physiol. 275:RI921-RI927, 1998.

Collister, J.P. and J.W. Osborn. The area postrema does not modulate long-term salt sensitivity of arterial pressure. Am. J. Physiol. 275:RI209-RI217, 1998.

Osborn, J.W., J.P. Collister and S.H. Carlson. Angiotensin and osmoreceptor inputs to the area postrema: Role in long-term control of fluid homeostasis and arterial pressure. Clin. Exp. Pharm. Physiol. 27:443-449, 2000.

Collister, J.P., S. L. Soucheray and J.W. Osborn. The chronic hypotensive effects of losartan are not dependent on the actions of angiotensin II at AT2 receptors. J.Cardiovasc.Pharm. 39:107-116, 2002.

Jacob, F., P. Ariza and J.W. Osborn. Renal denervation chronically lowers arterial pressure independent of salt intake in normal rats. Am. J. Physiol. 284: H2302-H2310, 2003.

Osborn, J.W., P.A. Ariza-Nieto J.P. Collister, S. Soucheray, B. Zimmerman and S. Katz. Responsiveness versus Basal Activity of Plasma Angiotensin II as a Determinant of Arterial Pressure Salt-Sensitivity. Am.J. Physiol. 285: H2142-H2149, 2003.

Fine, D., P. Ariza and J.W. Osborn. Does whole body autoregulation mediate the hemodynamic responses to increased dietary salt in rats with clamped angiotensin II? Am.J.Physiol. 285:H2760-H2678, 2003.

Wotus, C. W., J.W. Osborn, P. Ariza and W. C. Engeland. Regulation of corticosterone production by vasopressin during water-restriction and after drinking in rats. J. Neuroendocrinology 78:301-311, 2003.

Osborn, J.W., F. Jacob and P. Guzman. A neural set point for long-term control of arterial pressure: beyond the arterial baroreceptor reflex. Am. J. Physiol. 288:R846-R855, 2005.

Osborn, J.W. Set points and long-term control of arterial pressure: A theoretical argument for a long-term arterial pressure control system in the brain rather than the kidney. Clin. Exp. Physiol. Pharmacol. 32:384-394, 2005

Evans, R.G., S.C. Malpas, J.W. Osborn and G.D. Fink. Neural, hormonal and renal interactions in long-term blood pressure control. Clin.Exp.Physiol.Pharm. 32:372-373, 2005.

Jacob, F., B.G. LaBine, P. Ariza, S.A. Katz and J.W.Osborn. Renal denervation causes chronic hypotension in rats: role of beta-1 adrenoceptor activity. Clin. Exp. Physiol. Pharm. 32: 255-262, 2005.

Collister, J.P. and J.W. Osborn. Role of a responsive sympathetic nervous system in the chronic hypotensive effects of losartan in normal rats. J.Cardiovasc. Pharm. 46:147-154, 2005.

Jacob, F., L.A. Clark, P.A. Guzman and J.W. Osborn. Role of renal nerves in the development of hypertension in the DOCA-salt model in rats: A telemetric approach. Am.J.Physiol. 289: H1519- H1529, 2005.

John W. Osborn, Ph.D.

Professor of Physiology

Selected Publications