Central cholinergic mechanism for control of urine volume and electrolyte excretion

1. Studies were conducted on urine volume and electrolyte excretion chiefly of Na and K in anaesthetized hydrated dogs. 2. Central injection of acetylcholine caused a dose dependent antidiuretic response but without any change in excretion of urinary Sodium (UNa) and Potassium (UK). 3. After central atropinization, antidiuretic response to acetylcholine was partially blocked without any effect on electrolyte excretion. 4. Intracerebroventricularly (I.C.V.) administered acetylcholine after vagotomy and spinalectomy, each done separately and together also elicited an antidiuretic response. There was no effect on electrolyte excretion. 5. It is thus suggested that acetylcholine may be acting on central cholinergic receptors concerned with A.D.H. release.