title: A study of the effect of 8-aminoquinolines (primaquine, pamaquine, pentaquine) on the guinea-pig isolated ileum.
abstract: Primaquine (10(-6) to 4.10(-5) M), an antimalarial drug, has stimulatory effects on the guinea-pig ileum which seem to be related to stimulation of histaminergic H1-receptors. Preincubation of the preparations with compound 48/80 greatly inhibits the primaquine induced contractions, indicating that they should result from histamine release. On the other hand, primaquine (from 10(-6) M) like 2 other 8-aminoquinolines, pamaquine and pentaquine, has inhibitory properties on the intramural cholinergic neurones of the ileum, and at higher concentrations (10(-5) M) exerts a direct inhibition on the smooth muscle.
mesh_terms: D000634:Aminoquinolines / Q000494:pharmacology*; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D004347:Drug Interactions; D004558:Electric Stimulation; D005260:Female; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D011319:Primaquine / Q000494:pharmacology; D011738:Pyrilamine / Q000494:pharmacology; D013618:Tachyphylaxis / Q000187:drug effects; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
chemical_list: D000634:Aminoquinolines; D000962:Antimalarials; D003189:p-Methoxy-N-methylphenethylamine; D006632:Histamine; C004331:pamaquine; D011738:Pyrilamine; D011319:Primaquine; C016038:pentaquine