Nantenine blocks muscle contraction and Ca2+ transient induced by noradrenaline and K+ in rat vas deferens

Nantenine blocks muscle contraction and Ca2+ transient induced by noradrenaline and K+ in rat vas deferens

Author Ribeiro, R. D. Google Scholar
Garcez-do-Carmo, Lucia Autor UNIFESP Google Scholar
Vladimirova, I Google Scholar
Jurkiewicz, N. H. Google Scholar
Jurkiewicz, A. Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract The effect of nantenine, an aporphine alkaloid isolated from Ocotea macrophylla H.B.K., was studied on contractions and Ca2+ translocation induced by noradrenaline, Ca2+, or K+ in the isolated rat vas deferens from reserpinized animals. Concentration-response curves of calcium chloride (CaCl2) were performed in the vas deferens, in a Ca2+-free nutrient solution, using potassium chloride (KCl, 80 mM) as a depolarizing agent. in these conditions, nantenine (2.35 X 10(-4) and 4.7 x 10(-4) M) significantly reduced the maximum contractions (E-max) of Ca2+ (IC50 = 2.6 x 10(-4) M) and noradrenaline (IC50 = 2.9 x 10(-4) M). the contractile responses were totally recovered after the withdrawal of nantenine. in addition, experiments performed to measure simultaneously the contraction and the increase of intracellular Ca2+ induced by noradrenaline (10(-5) M) or KCl (80 mM) showed that nantenine (2.35 x 10(-4) and 4.7 x 10(-4) M) significantly decreased both effects. the results suggest that a reversible block of Ca2+ entry could be involved on the non-competitive-like antagonism of nantenine in rat vas deferens. (C) 2003 Elsevier Science B.V. All rights reserved.
Keywords nantenine
aporphine
Ca2+ entry blocker
fura-2
smooth muscle
Vas deferens
rat
Language English
Date 2003-05-30
Published in European Journal of Pharmacology. Amsterdam: Elsevier B.V., v. 470, n. 1-2, p. 37-43, 2003.
ISSN 0014-2999 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 37-43
Origin http://dx.doi.org/10.1016/S0014-2999(03)01758-8
Access rights Closed access
Type Article
Web of Science ID WOS:000183428000006
URI http://repositorio.unifesp.br/handle/11600/27257

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