Abstract

The renal tubular transports of radioactively labeled acetylcholine and atropine were investigated in vivo in the chicken by use of the Sperben technique. The label excreted in the urine during infusion of ¹⁴C-acetylcholine was isolated and identified as nonmetabolized acetylcholine by high voltage electrophoresis, paper chromatography and reineckate precipitation. Evidence for the secretion of acetylcholine by the organic cation transport mechanism was established through inhibition of its tubular transport by competitors for this mechanism, quinine and cyanine dye no. 863. The cholinesterase inhibitors, paraoxon and physostigmine, or increases in the amount of infused acetyicholine produced an enhancement of acetylcholine transport efficiency. Atropine was also transported by the cation transport mechanism in the renal tubule of the chicken and inhibited the transport of acetylcholine. Other inhibitors of acetylcholine transport were choline and cocaine.