['A marked suppression of acetylcholine (ACh) release from myenteric nerves in the inflamed intestine of rats infected by Trichinella spiralis has been shown. In this model, there is increased expression of interleukin 1 beta (IL-1 beta) in the myenteric plexus. Therefore, the ability of IL-1 beta to alter ACh release in longitudinal muscle-myenteric plexus (LMMP) preparations from noninfected rats was examined.', 'LMMP preparations were loaded with [3H]choline before stimulation by KCl or electrical field stimulation. ACh release was recorded by measuring 3H in the superfusate. Experiments were performed in the presence or absence of human recombinant IL-1 beta.', 'IL-1 beta had no immediate effect on the basal or stimulated release of ACh. A marked suppression of ACh release was observed in tissues that had been preincubated with IL-1 beta for 60 minutes or more. The effect of IL-1 beta was concentration and time dependent with maximum suppression occurring with 10 ng/mL of the cytokine after a 90-minute incubation. The action of human recombinant (hr) IL-1 beta was abolished by boiling the cytokine for 20 minutes and was prevented by preincubating the cytokine with neutralizing antibody. The IL-1 beta effect was also blocked by cycloheximide and was spontaneously reversible after 60 minutes.'] Does human recombinant interleukin 1 beta suppress acetylcholine release from rat myenteric plexus?