title: Functional antagonism by calcium of an intrinsic opioid mechanism in the guinea-pig isolated ileum.
mesh_terms: D015761:4-Aminopyridine; D000631:Aminopyridines / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D009270:Naloxone / Q000494:pharmacology; D010528:Peristalsis / Q000187:drug effects; D011957:Receptors, Opioid / Q000187:drug effects*
chemical_list: D000631:Aminopyridines; D011957:Receptors, Opioid; D009270:Naloxone; D015761:4-Aminopyridine; D002118:Calcium