K transfer in ureter ligated dogs loaded with KCl.

In control ureter ligated dogs infused with 2 mEq KCl/kg.h until prelethal electrocardiographic changes of hyperkalemic cardiotoxicity appear, a kaluresis independent K homeostatic mechanism delays the development of hyperkalemia by transferring some 55% of administered K to intracellular fluid. In preparations with cervical trunk vagotomy the proportion increases to about 70%; but not if the adrenals are simultaneously removed or denervated. A dosage of atropine that crosses the blood-brain barrier is an exact substitute for cervical vagotomy. Our findings suggest that ureter ligated K loaded dogs, ureteral and/or renal afferent vagal fibres to the brain release a "muscarinic" neurotransmitter(s) that modulated neural traffic in rami of splanchnic nerves to the adrenal medulla.