Effect of chronic central alpha-hANP administration on blood pressure, water and electrolyte balance in rats

Relatively few studies have evaluated the chronic effects of atrial natriuretic polypeptide (ANP) administration into the central nervous system on peripheral cardiovascular and renal function under conditions of expanded extracellular fluid volume. The present investigation examined the effects of synthetic alpha-human atrial natriuretic polypeptide (alpha-hANP) chronically infused into the cerebroventriculum of rats loaded with 0.9% saline. Measurements of the arterial blood pressure, water and electrolyte balances were carried out during a 4-day central ventricular infusion of alpha-hANP. Significant increases in daily urine volume and urinary sodium and chloride excretion were observed, but no changes of arterial blood pressure occurred. These results indicate that elevated levels of ANP in the CSF can influence sodium and water excretion, but do not appear to influence arterial pressure.