• Andresen, Michael (PI)

Project: Research project

Project Details


The role of baroreceptor inputs in the modulation of sympathetic nerve
activity both under control conditions and under conditions known to alter
baroreceptor characteristics will be examined. Sympathetic nerve activity
will be studied at three different levels. In the first phase of the
study, activity of single afferent fibers from sympathetic nerves will be
measured in anesthetized rabbits. In the second phase activity from whole
sympathetic nerves will be recorded in anesthetized rabbits. In the final
phase chronic recordings of sympathetic nerve activity will be made in
conscious, unanesthetized rabbits. The studies will primarily be concerned
with renal sympathetic nerves but cardiac and muscle sympathetic nerves
will also be included. In all phases ofthis study, surgically implanted
perivascular balloons will be used to briefly raise and lower blood
pressure to determine the relationship of sympathetic nerve activity to
mean arterial blood pressure. Curve characteristics including the blood
pressue at which activity is minimal, the slope on gain and the range o
activity for the barofeflex relationship will be determined. Prolonged
alteration of resting blood pressure will be used to study the effects of
acute barcreceptor resetting on baroreflex modulation of sympathetic
activity. Single fiber efferents will be examined to determine whether
whole nerve activity reflects responses in a homogenous or heterogeneous
population of individual efferents and thus to interpret the response of
whole nerve sympathetic activity. The contribution of afferent input from
high and low pressure baroreceptors will be studied by selective aortic and
carotid sinus denervations. More specific knowledge of the baroreceptor
involvement in modifying sympathetic outflow is important to understanding
the neural control of the circulation during prolonged blood pressure
alterations, such as duing therapeutic drug treatment.
Effective start/end date1/1/8312/31/86


  • National Institutes of Health


  • Medicine(all)


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