Different pathways for Ca2+ mobilization by angiotensin II and carbachol in the circular muscle of the guinea-pig ileum

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dc.contributor.authorShimuta, S. I.
dc.contributor.authorBorges, ACR
dc.contributor.authorPrioste, R. N.
dc.contributor.authorPaiva, T. B.
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.date.accessioned2016-01-24T12:30:45Z
dc.date.available2016-01-24T12:30:45Z
dc.date.issued1999-02-12
dc.description.abstractCa2+ pathways activated by angiotensin II and carbachol were evaluated in the circular muscle of the guinea-pig ileum by recording mechanical and electrical activities. Transient contractions induced by angiotensin II were greatly reduced by Ca2+ removal from the medium whereas carbachol-induced responses were not significantly altered. Nifedipine had no effect on the responses to both agonists. A high concentration of tetrodotoxin (0.1 mu M) inhibited angiotensin II-induced contractile responses without affecting the depolarization, whereas 1 mM Ni2+ inhibited the mechanical and electrical effects. Neither tetrodotoxin nor Ni2+ affected carbachol-induced effects. These results indicate that angiotensin II-induced phasic contractions depend on extracellular Ca2+ but not on voltage-dependent L-type Ca2+ channels. It is suggested that angiotensin II activates Ni2+-sensitive Na+ and non-specific cationic channels, whereas the responses to carbachol are dependent on receptor-activated Ca2+ release. Furthermore the different response of the longitudinal and circular muscles to the inhibitory effects of tetrodotoxin and Ni2+ on the angiotensin II- and carbachol-induced contractions indicates that these agonists exert their own myogenic effects on each layer and are able to trigger different Ca2+ mobilization pathways. (C) 1999 Elsevier Science B.V. All rights reserved.en
dc.description.affiliationUniversidade Federal de São Paulo, Escola Paulista Med, Dept Biophys, BR-04023062 São Paulo, Brazil
dc.description.affiliationUnifespUniversidade Federal de São Paulo, Escola Paulista Med, Dept Biophys, BR-04023062 São Paulo, Brazil
dc.description.sourceWeb of Science
dc.format.extent59-66
dc.identifierhttp://dx.doi.org/10.1016/S0014-2999(98)00919-4
dc.identifier.citationEuropean Journal of Pharmacology. Amsterdam: Elsevier B.V., v. 367, n. 1, p. 59-66, 1999.
dc.identifier.doi10.1016/S0014-2999(98)00919-4
dc.identifier.issn0014-2999
dc.identifier.urihttp://repositorio.unifesp.br/handle/11600/26033
dc.identifier.wosWOS:000078672000009
dc.language.isoeng
dc.publisherElsevier B.V.
dc.relation.ispartofEuropean Journal of Pharmacology
dc.rightsinfo:eu-repo/semantics/restrictedAccess
dc.rights.licensehttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dc.subjectangiotensin IIen
dc.subjectcarbacholen
dc.subjectileal circular muscleen
dc.subjectmechanical activityen
dc.subjectelectrical activityen
dc.subjecttetrodotoxinen
dc.subjectNi2+en
dc.titleDifferent pathways for Ca2+ mobilization by angiotensin II and carbachol in the circular muscle of the guinea-pig ileumen
dc.typeinfo:eu-repo/semantics/article
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