AJP - Regulatory, Integrative and Comparative Physiology, Vol 244, Issue 6 815-R822, Copyright © 1983 by American Physiological Society
Sodium excretion following lesions of preoptic recess periventricular tissue in the rat
S. L. Bealer
Electrolytic lesions of periventricular tissue surrounding the
anteroventral third ventricle (AV3V) results in chronic hypernatremia and
attenuates natriuresis following several experimental treatments. The
present investigation was designed to determine if AV3V periventricular
ablation results in acute postlesion alterations in sodium metabolism.
Urinary sodium excretion was measured during 2-h periods for 6 h, and then
daily for 7 days following either electrolytic ablation of AV3V
periventricular tissue or control surgery. Similar measurements were
carried out on unoperated control animals, and rats which had received
either renal denervations or subcutaneous injections of deoxycorticosterone
(DOC) prior to surgery. Lesions of the tissue surrounding the AV3V resulted
in a natriuresis and polyuria that was not prevented by renal denervation
or DOC treatment and was accompanied by a pressor response and decreased
glomerular filtration rate. The initial natriuresis was followed by 2 days
of sodium retention, which exceeded the amount necessary to restore sodium
balance. These data demonstrate that ablation of AV3V periventricular
tissue results in acute alterations in sodium metabolism, and support the
hypothesis that tissue surrounding the AV3V contains neural elements
critical for normal sodium regulation.
