Activity of boldine on rat ileum.
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.
Speisky
H
H
Biochemical Pharmacology Unit, University of Chile, Santiago.
Squella
J A
JA
Núñez-Vergara
L J
LJ
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
D001060:Aporphines; C011686:boldine; D000109:Acetylcholine