title: Enkephalins inhibit intestinal motility: mode of action.
abstract: In the guinea pig isolated terminal ileum the opioid pentapeptides, methionine-enkephalin and leucine-enkephalin, dose-dependently inhibit contractile responses induced by electrical field stimulation releasing endogenous acetylcholine, and by specific noncholinergic compounds including histamine, barium chloride, and beta-acetyl-digoxin. Tissue levels of cAMP and cGMP remain unchanged. We conclude that enkephalins exert their effects by a direct action at or within the muscle cell and may play a physiological role in the local control of the gut smooth muscle motility.
mesh_terms: D000818:Animals; D004745:Enkephalins / Q000494:pharmacology*; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006168:Guinea Pigs; D007082:Ileum; D066298:In Vitro Techniques; D009130:Muscle, Smooth / Q000378:metabolism; D009712:Nucleotides, Cyclic / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*
chemical_list: D004745:Enkephalins; D009712:Nucleotides, Cyclic; D009842:Oligopeptides