Effect of intracerebroventricular clonidine on some renal functions in rats.

In male Charles Foster rats, intracerebroventricular clonidine (0.2, 1.0, 10 mmol/l) caused dose dependent increase in the urine output and sodium excretion (P less than 0.01). Urinary creatinine excretion was decreased to a significant level (P less than 0.02). Urinary potassium excretion was increased but was not dose dependent. Maximal increase in the urine volume occurred during first hour of clonidine administration. Intraperitoneal administration of clonidine in similar molar concentration failed to produce changes in the urine volume. The results indicate that clonidine-induced diuresis is centrogenic and is attributed to the inhibition of the release of vasopressin from central hypothalamoneurohypophyseal axis.