Key Points
- To determine whether sodium and angiotensin interact centrally within the third cerebral ventricle to regulate thirst, antidiuresis, and renal sodium excretion.
- Administered 30-minute infusions of angiotensin alone, hypertonic sodium chloride alone, or both combined into the third brain ventricle of goats.
- Tested responses across both normal hydration states and hydrated conditions, with and without salt supplementation.
- Assessed drinking behavior, urine volume inhibition (antidiuresis), and renal sodium excretion over time.
- Simultaneous infusion of angiotensin and hypertonic sodium chloride markedly potentiated both dipsogenic (drinking) behavior and antidiuretic responses compared to either substance alone.
- Angiotensin strongly enhanced the natriuretic response to ventricular hypertonic saline in hydrated goats, resulting in extreme renal sodium excretion in salt-supplemented animals.
- The sodium-angiotensin synergy was less pronounced during normal water balance, and the delayed time course of natriuresis suggested mediation by a humoral factor.
Structured PICO
PPopulationGoats in normal water balance and hydrated animals
IInterventionSimultaneous infusion of angiotensin and hypertonic NaCl into the 3rd brain ventricle for 30 min
CComparatorInfusions of angiotensin alone (in slightly hypotonic saline) and of hypertonic NaCl alone
OOutcomeWater and salt balances (drinking behavior, water diuresis, natriuresis)surrogate
Simultaneous central administration of angiotensin and hypertonic NaCl synergistically potentiates thirst, antidiuresis, and natriuresis in goats, suggesting intracellular sodium concentration regulates these brain mechanisms.