title: The enantiomers of the dihydropyridine derivative H 160/51 show opposite effects of stimulation and inhibition.
abstract: H 160/51 is a calcium agonistic 1,4-dihydropyridine. Its optical isomers were now found to have opposing actions in the cat papillary muscle and rat portal vein. The inhibitory (+)-enantiomer had potencies of the same order as those of the stimulatory (-)-enantiomer. However the racemate and the (-)-enantiomer had approximately the same potencies and intrinsic activities. A model is presented to account for the fact that the effects of the inhibitory (+)-enantiomer can be concealed in the effects of the racemate of H 160/51.
mesh_terms: D000818:Animals; D002415:Cats; D003864:Depression, Chemical; D004095:Dihydropyridines; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009132:Muscles / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects; D011169:Portal Vein / Q000187:drug effects; D011725:Pyridines / Q000494:pharmacology*; D013237:Stereoisomerism; D013268:Stimulation, Chemical
chemical_list: D004095:Dihydropyridines; D011725:Pyridines; C049023:H 160-51; C038806:1,4-dihydropyridine