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Impact of the whole-cell patch-clamp configuration on the pharmacological assessment of the hERG channel: trazodone as a case example.
Rodriguez-Menchaca, Aldo A; Ferrer, Tania; Navarro-Polanco, Ricardo A; Sanchez-Chapula, Jose A; Moreno-Galindo, Eloy G.
Afiliação
  • Rodriguez-Menchaca AA; Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico.
  • Ferrer T; Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico.
  • Navarro-Polanco RA; Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico.
  • Sanchez-Chapula JA; Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico.
  • Moreno-Galindo EG; Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico. Electronic address: eloy@ucol.mx.
J Pharmacol Toxicol Methods ; 69(3): 237-44, 2014.
Article em En | MEDLINE | ID: mdl-24412489
INTRODUCTION: Voltage- and state-dependent blocks are important mechanisms by which drugs affect voltage-gated ionic channels. However, spontaneous (i.e. drug-free) time-dependent changes in the activation and inactivation of hERG and Na(+) channels have been reported when using conventional whole-cell patch-clamp in HEK-293 cells. METHODS: hERG channels were heterologously expressed in HEK-293 cells and in Xenopus laevis oocytes. hERG current (IhERG) was recorded using both conventional and perforated whole-cell patch-clamp (HEK-293 cells), and two microelectrode voltage-clamp (Xenopus oocytes) in drug-free solution, and in the presence of the drug trazodone. RESULTS: In conventional whole-cell setup, we observed a spontaneous time-dependent hyperpolarizing shift in the activation curve of IhERG. Conversely, in perforated patch whole-cell (HEK-293 cells) or in two microelectrode voltage-clamp (Xenopus oocytes) activation curves of IhERG were very stable for periods ~50min. Voltage-dependent inactivation of IhERG was not significantly altered in the three voltage clamp configurations tested. When comparing voltage- and state-dependent effects of the antidepressant drug trazodone on IhERG, similar changes between the three voltage clamp configurations were observed as under drug-free conditions. DISCUSSION: The comparative analysis performed in this work showed that only under conventional whole-cell voltage-clamp conditions, a leftward shift in the activation curve of IhERG occurred, both in the presence and absence of drugs. These spontaneous time-dependent changes in the voltage activation gate of IhERG are a potential confounder in pharmacological studies on hERG channels expressed in HEK-293 cells.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Trazodona / Técnicas de Patch-Clamp / Canais de Potássio Éter-A-Go-Go Limite: Animals / Humans Idioma: En Revista: J Pharmacol Toxicol Methods Assunto da revista: FARMACOLOGIA / TOXICOLOGIA Ano de publicação: 2014 Tipo de documento: Article País de afiliação: México País de publicação: Estados Unidos
Texto completo
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Trazodona / Técnicas de Patch-Clamp / Canais de Potássio Éter-A-Go-Go Limite: Animals / Humans Idioma: En Revista: J Pharmacol Toxicol Methods Assunto da revista: FARMACOLOGIA / TOXICOLOGIA Ano de publicação: 2014 Tipo de documento: Article País de afiliação: México País de publicação: Estados Unidos