Relationship between excitation of vagal inhibitory neurons and nucleoside release: estimation by paper...

Experiments were carried out to determine whether ATP or its metabolites are increased in vascular perfusate from the guinea pig stomach in response to stimulation of vagal non-adrenergic innervation. Compounds in the perfusate were identified by paper chromatography and by determination of the absorption maximum in ultraviolet rays. The following compounds were detected in the perfusate from the resting preparation; hypoxanthine, inosine and uridine, a small amount of xanthine and adenosine and two other non-adenine compounds. When the nutrient medium containing ATP was recycled, hypoxanthine and inosine, and a small amount of adenosine and AMP increased. On the other hand, stimulation of the non-adrenergic inhibitory nerve did not produce any appreciable increase in these compounds in the perfusate. These findings do not support the idea that the transmitter substance responsible for relaxation of the guinea pig stomach in response to stimulation of the vagus nerve is ATP or its related compounds.