title: Involvement of β adrenergic receptors in spasmolytic effect of caulerpine on guinea pig ileum.
abstract: Previously, we demonstrated that caulerpine has spasmolytic effect on guinea pig ileum. The aim of this study was to investigate pathways of its spasmolytic action. We test caulerpine against phasic contractions induced by carbachol in the circular layer of guinea pig ileum and this alkaloid did not inhibit these contractions, indicating that caulerpine did not interfering with the mobilisation of Ca2+from intracellular stores. Additionally, the spasmolytic effect of caulerpine did not involve K+channels. Furthermore, we observed that α2-adrenergic receptors were not involved in the spasmolytic effect of caulerpine, since the relaxation curve induced by caulerpine was not shifted in the presence of yohimbine (α2-adrenergic antagonist). However, in the presence of propranolol (β-adrenergic antagonist), the relaxation curve induced by caulerpine was right-shifted, resulting in a fivefold increase in EC50. Thus, a possible mechanism for the spasmolytic action of caulerpine is the activation of β-adrenergic receptors.
authors.affiliation: a Biotechonology Center , Federal University of Paraíba , João Pessoa , Brazil.
authors.forename: Luiz Henrique Agra
authors.initials: LHA
authors.lastname: Cavalcante-Silva
authors.affiliation: b Institute of Biological Sciences and Health , Federal University of Alagoas , Maceió , Brazil.
authors.forename: Ana Carolina de Carvalho
authors.initials: ACC
authors.lastname: Correia
authors.affiliation: c Postgraduate Program in Natural Products and Synthetic Bioactive , Federal University of Paraíba , João Pessoa , Brazil.
authors.forename: Jéssica Celestino Ferreira
authors.initials: JCF
authors.lastname: Sousa
authors.affiliation: c Postgraduate Program in Natural Products and Synthetic Bioactive , Federal University of Paraíba , João Pessoa , Brazil.|d Department of Pharmaceutical Sciences , Federal University of Paraíba , João Pessoa , Brazil.
authors.forename: José Maria
authors.initials: JM
authors.lastname: Barbosa-Filho
authors.affiliation: c Postgraduate Program in Natural Products and Synthetic Bioactive , Federal University of Paraíba , João Pessoa , Brazil.|d Department of Pharmaceutical Sciences , Federal University of Paraíba , João Pessoa , Brazil.
authors.forename: Bárbara Viviana de Oliveira
authors.initials: BVO
authors.lastname: Santos
authors.affiliation: e Department of Systematics and Ecology , Federal University of Paraíba , João Pessoa , Brazil.
authors.forename: George Emmanuel C
authors.initials: GEC
authors.lastname: de Miranda
authors.affiliation: b Institute of Biological Sciences and Health , Federal University of Alagoas , Maceió , Brazil.
authors.forename: Magna Suzana
authors.initials: MS
authors.lastname: Alexandre-Moreira
authors.affiliation: c Postgraduate Program in Natural Products and Synthetic Bioactive , Federal University of Paraíba , João Pessoa , Brazil.|f Department of Physiology and Pathology , Federal University of Paraíba , João Pessoa , Brazil.
authors.forename: Fabiana de Andrade
authors.initials: FA
authors.lastname: Cavalcante
keywords: Caulerpine; adrenergic receptors; guinea pig ileum; spasmolytic effect