AJP - Renal Physiology, Vol 244, Issue 4 376-F382, Copyright © 1983 by American Physiological Society
Hemodynamic mechanisms in CNS-induced natriuresis in the conscious rat
S. L. Bealer
These experiments were designed to determine 1) the effects of increased
CSF sodium concentration on renal hemodynamics in the conscious rat, and 2)
the role of the periventricular tissue surrounding the anteroventral third
ventricle (AV3V) in the natriuretic and hemodynamic responses during this
treatment. After electrolytic lesions of AV3V periventricular tissue or
control surgery, blood pressure, glomerular filtration rate, effective
renal blood flow, urine volume, and sodium and potassium excretion were
measured before and during intraventricular (IVT) infusion of either
isotonic or hypertonic saline solutions in conscious hydrated rats. Blood
pressure, glomerular filtration rate, and sodium and potassium excretion
increased during IVT infusion of concentrated sodium solutions in control
rats but not in animals with lesions in the AV3V region. These data support
the hypothesis that the natriuretic response to increased CSF sodium
concentration in the rat is due to a pressor response and/or increased
glomerular filtration rate and demonstrate that ablation of AV3V
periventricular tissue blunts the natriuretic response, possibly through
diminished central pressor mechanisms and/or decreased central control of
glomerular filtration rate.
