title: Activity of boldine on rat ileum.
abstract: Boldine shows a concentration-dependent relaxation effect on the rat ileum preparation with a pD2 of 3.77 +/- 0.12. The alkaloid also produces a concentration-dependent parallel shift of the curve-response to acetylcholine, therefore it directly interferes with the cholinergic mechanism associated with the contraction, behaving as a competitive antagonist with a pA2 of 4.78 +/- 0.19. On the other hand, boldine produces a nonparallel shift of the contraction response induced by barium, revealing the occurrence of a non-competitive antagonism. This effect could be the result of interference with intracellular events associated with the barium-induced changes in calcium pools.
authors.affiliation: Biochemical Pharmacology Unit, University of Chile, Santiago.
authors.forename: H
authors.initials: H
authors.lastname: Speisky
authors.forename: J A
authors.initials: JA
authors.lastname: Squella
authors.forename: L J
authors.initials: LJ
authors.lastname: Núñez-Vergara
mesh_terms: D000109:Acetylcholine / Q000037:antagonists & inhibitors; D000818:Animals; D001060:Aporphines / Q000494:pharmacology*; D005260:Female; D007082:Ileum / Q000187:drug effects*; D066298:In Vitro Techniques; D009126:Muscle Relaxation / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D001060:Aporphines; C011686:boldine; D000109:Acetylcholine