title: Effects of external calcium ions and strontium ions on interactions of isoprenaline and its competitive inhibitor with beta-adrenoceptors in the intestinal smooth muscle.
abstract: The effects were tested of Ca ions and Sr ions on interactions of isoprenaline and its competitive inhibitor with beta-adrenoceptors in the taenia caecum from the guinea pig. Ca ions were involved in the combination of isoprenaline with the beta-adrenoceptors but not involved in the combination of the competitive inhibitor with the beta-adrenoceptors. Sr ions could not substitute for Ca ions in the isoprenaline--receptor interaction.
mesh_terms: D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology*; D002432:Cecum / Q000187:drug effects; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D011941:Receptors, Adrenergic / Q000187:drug effects*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D013324:Strontium / Q000494:pharmacology*
chemical_list: D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D007545:Isoproterenol; D002118:Calcium; D013324:Strontium