Sites of actions of adenosine in intrinsic cholinergic nerves of ileal longitudinal muscle from guinea pig.

The sites of presynaptic actions of adenosine on electrically stimulated longitudinal muscle strip of guinea pig ileum were studied with a special dual organ bath. Local stimulation (0.1 Hz) of the anal part of the strip induced a twitch response in the stimulated part and in the non-stimulated oral part; both of these twitch responses were depressed by an application of adenosine to the anal, stimulated part of the strip. The present results suggested that electrical stimulation applied to the anal part of the strip travelled along the network of Auerbach's plexus in the oral direction, and adenosine might depress such conduction in cholinergic nerve fibers in addition to nerve terminals.