1.The effects of hexamethonium, given into the lateral ventricle, on the renal function of the rabbits were examined, and its influence on the renal effects of intraventricular carbachol were also examined.
2. Intraventricular hexamethonium(300 mg/Kg) tended to slightly decrease urine flow rate, renal blood flow and glomerular filtration rate, but urinary excreted amounts of sodium, Cosm and free water reabsorption were decreased significantly from 20 or 40 min. after intraventricular hexamethonium.
3. Intraventricular carbachol (2mg/Kg) produced statistically significant diuresis, natriuresis and increased change of Cosm without significant changes of glomerular filtration rate and renal blood flow rate.
4. The effects of intraventricular carbachol were not influenced by the intraventricular hexamethonium pretreatment, but completely abolished by the intraventricular atropine pretreatment.
From these above results, it is suggested that the centrally mediated diuresis of carbachol is not due to renal homodynamic changes or ADH release, but related to other central muscarinic natriuresis.
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