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Eugenol-induced contractions of saponin-skinned fibers are inhibited by heparin or by a ryanodine receptor blocker.
Lofrano-Alves, Marco S; Oliveira, Edson L; Damiani, Carlos E N; Kassouf-Silva, Ilana; Fogaça, Rosalvo T H.
Afiliação
  • Lofrano-Alves MS; Departamento de Fisiologia, Setor de Ciências Biológicas, Centro Politécnico, Universidade Federal do Paraná, Curitiba, Paraná, Brazil.
Can J Physiol Pharmacol ; 83(12): 1093-100, 2005 Dec.
Article em En | MEDLINE | ID: mdl-16462908
The effects of eugenol on the sarcoplasmic reticulum (SR) and contractile apparatus of chemically skinned skeletal muscle fibers of the frog Rana catesbeiana were investigated. In saponin-skinned fibers, eugenol (5 mmol/L) induced muscle contractions, probably by releasing Ca(2+) from the SR. The Ca(2+)-induced Ca(2+) release blocker ruthenium red (10 micromol/L) inhibited both caffeine- and eugenol-induced muscle contractions. Ryanodine (200 micromol/L), a specific ryanodine receptor/Ca(2+) release channel blocker, promoted complete inhibition of the contractions induced by caffeine, but only partially blocked the contractions induced by eugenol. Heparin (2.5 mg/mL), an inositol 1,4,5-trisphosphate (InsP3) receptor blocker, strongly inhibited the contractions induced by eugenol but had only a small effect on the caffeine-induced contractions. Eugenol neither altered the Ca(2+) sensitivity nor the maximal force in Triton X-100 skinned muscle fibers. These data suggest that muscle contraction induced by eugenol involves at least 2 mechanisms of Ca(2+) release from the SR: one related to the activation of the ryanodine receptors and another through a heparin-sensitive pathway.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Eugenol / Heparina / Músculo Esquelético / Fibras Musculares Esqueléticas / Canal de Liberação de Cálcio do Receptor de Rianodina Limite: Animals Idioma: En Revista: Can J Physiol Pharmacol Ano de publicação: 2005 Tipo de documento: Article País de afiliação: Brasil País de publicação: Canadá
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Eugenol / Heparina / Músculo Esquelético / Fibras Musculares Esqueléticas / Canal de Liberação de Cálcio do Receptor de Rianodina Limite: Animals Idioma: En Revista: Can J Physiol Pharmacol Ano de publicação: 2005 Tipo de documento: Article País de afiliação: Brasil País de publicação: Canadá