Department of Internal Medicine
Ulla C. Kopp, Ph.D.
Professor (Emeritus) of Medicine and Pharmacology
Dr. Kopp's research interests include renorenal reflexes in normotension and hypertension.
This research project focuses on the kidney as a sensory
organ. Sensory nerves, located in the renal pelvic wall are activated
by increases in renal pelvic pressure of a magnitude seen during moderate
volume expansion. The integrated response to this activation is a natriuresis.
The elicited reflex response to activation of renal mechanosensory nerves
is called a renorenal reflex. The mechanisms involved in activation of
renal sensory nerves include the neuropeptide substance P released in
response to increased prostaglandin synthesis. The natriuretic nature
of the renorenal reflexes suggests that this reflex mechanism contributes
to total body sodium and fluid volume balance by assisting in the excretion
of sodium and water. Indeed, our studies show that in comparison to low
dietary sodium intake conditions, high dietary sodium intake enhances
the renorenal reflex response. The overall importance of this renorenal
reflex diuresis and natriuresis was further evaluated by removing it
by afferent renal denervation. Our data show that afferent renal denervation
results in the development of increased MAP, presumably to facilitate
natriuresis and establishment of sodium balance during high NaCl. Further evidence for the importance of this natriuretic reflex is derived from our studies showing that the renorenal reflex control of renal function is impaired in conditions of sodium retention. e.g., hypertension, cardiac heart failure and diabetes.