RT info:eu-repo/semantics/article
T1 Putrescine modulation of acute activation of the β-adrenergic system in the left atrium of rat
A1 Bordallo, Carmen
A1 Cantabrana, Begoña
A1 Velasco, Lucía
A1 Secades, Lorena
A1 Meana González, Clara
A1 Méndez, Miriam
A1 Bordallo, Javier
A1 Sánchez, Manuel
AB Endogenous polyamines mediate acute metabolic effects and cardiac hypertrophy associated to β-adrenoceptor stimulation. The aim of this study is to characterize the role of polyamines on β-adrenoceptor system mediated responses. To this end, the functional interaction of polyamine modifying drugs on isoproterenol-elicited cardiotonic effect, in isolated left atria of male Wistar rats, and their effects on [3H]dihydroalprenolol (DHA) binding on β-adrenoceptors and on adenylyl cyclase activity of membrane heart were studied. Polyamines interact with β-adrenoceptors in rat heart, as shown by the displacement of [3H]DHA binding. Furthermore, putrescine (but not spermidine or spermine) increased adenylyl cyclase activity, elicited a positive inotropism and increased intracellular cAMP. The putrescine effect on adenylyl cyclase was not antagonized by the β-adrenoceptors blockers, alprenolol and ICI-118,551, and facilitated the isoproterenol effect. Neither alprenolol, atenolol nor ICI-118,551 antagonized putrescine-elicited positive inotropism.However, the effectwas abolished in preparations with desensitized β-adrenoceptors. α-Difluoromethylornithine, an inhibitor of ornithine decarboxylase, antagonized the effect of isoproterenol on inotropism and cAMP increase. In addition, putrescine might elicit effects by mechanisms independent of β-adrenoceptor system, since in left atria with functional desensitized receptors an interactionwith ouabain-elicited  cardiotonic effectwas observed. These results suggest that putrescine may act as a lowaffinity agonist on β-adrenoceptors and modulate acute responses mediated by β-adrenoceptors. These findings may be of importance in the physiology and in diseases involving cardiac β-adrenoceptors.
SN 0014-2999
YR 2008
FD 2008
LK https://uvadoc.uva.es/handle/10324/74252
UL https://uvadoc.uva.es/handle/10324/74252
LA spa
NO European Journal of Pharmacology, noviembre 2008, vol. 598, n. 1-3, p. 68-74
DS UVaDOC
RD 04-jun-2025