Evidence that adenosine triphosphate or a related nucleotide is the transmitter substance released by non‐adrenergic inhibitory nerves in the gut

Abstract

Summary: . Stimulation of the vagal non‐adrenergic inhibitory innervation caused the release of adenosine and inosine into vascular perfusates from the stomachs of guinea‐pigs and toads. . Stimulation of portions of Auerbach's plexus isolated from turkey gizzard caused the release of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP). . ATP, added to solutions perfused through the toad stomach vasculature, was broken down to adenosine, inosine and adenine. . Of a series of purine and pyrimidine derivatives tested for inhibitory activity on the guinea‐pig isolated taenia coli, ATP and ADP were the most potent. . ATP caused inhibition of twelve other gut preparations previously shown to contain non‐adrenergic inhibitory nerves. The inhibitory action of ATP was not prevented by tetrodotoxin. . Quinidine antagonized relaxations of the guinea‐pig taenia coli caused by catecholamines or adrenergic nerve stimulation. Higher concentrations of quinidine antagonized relaxations caused by ATP or non‐adrenergic inhibitory nerve stimulation. . When tachyphylaxis to ATP had been produced in the rabbit ileum, there was a consistent depression of the responses to non‐adrenergic inhibitory nerve stimulation but not of responses to adrenergic nerve stimulation. . It is suggested that ATP or a related nucleotide is the transmitter substance released by the non‐adrenergic inhibitory innervation of the gut.