CARDIOVASCULAR MECHANORECEPTORS IN GENETIC HYPERTENSION

Project: Research project

Project Details

Description

Excessive salt-ingestion in man has long been associated with an increased
risk of developing hypertension, yet the mechanisms by which salt acts are
poorly understood. In the Dahl rat model, Salt-Sensitive rats (DS) develop
elevated blood pressures on a high salt (HS) diet while Salt-Resistant rats
(DR) remain normotensive. Recent research has suggested that there is a
significant neurogenic contribution to the development of hypertension in
DS rats. The arterial and cardiopulmonary baroreflexes of DS rats are
depressed even before exposure to high salt and the subsequent development
of hypertension. This project will test whether abnormal function of the
cardiovascular mechanoreceptors contributes to these decreases in
baroreflex sensitivity in DS rats. I will use two in vitro preparations to
study quantitatively the response characteristics of aortic arch
baroreceptors and cardiopulmonary mechanoreceptors located in the superior
vena cava just outside the right atrium. This in vitro approach allows a
much more precise control of experimental conditions including
reproducible, well-defined pressure inputs and ionic environment. In
addition, the geometry of the vessel walls in which these mechanoreceptors
are found can be closely approximated by a simple right cylinder so that
the contribution of vessel wall distensibility and mechanics can be
assessed through measurements of vessel diameter. Single mechanoreceptors
will be tested for steady-state discharge characteristics including
threshold and suprathreshold sensitivity, for rapid resetting to changes in
the conditioning pressure and for sensitivity to changes in external ionic
concentrations. Of particular importance are the comparisons of an inbred,
nonselected strain of control rats (Sprague-Dawley) to both DS and DR and
the effect of low salt and high salt diets.
StatusFinished
Effective start/end date7/1/856/30/89

Funding

  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health

ASJC

  • Medicine(all)

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