Effect of caffeine on K+ efflux in frog skeletal muscle
- Autores
- Venosa, Roque Alberto; Hoya, Arturo
- Año de publicación
- 1999
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- The exposure of frog skeletal muscle to caffeine (3–4 mM) generates an increase of the K+ (42K+) efflux rate coefficient (k; K,o) which exhibits the following characteristics. First it is promoted by the rise in cytosolic Ca2+ ([Ca2+]i), because the effect is mimicked by ionomycin (1.25 µM), a Ca2+ ionophore. Second, the inhibition of caffeine-induced Ca2+ release from the sarcoplasmic reticulum (SR) by 40 µM tetracaine significantly reduced the increase in k; K,o (Δk; K,o). Third, charybdotoxin (23 nM), a blocker of the large-conductance Ca2+-dependent K+ channels (BKCa channels) reduced Δk; K,o by 22%. Fourth, apamin (10 nM), a blocker of the small-conductance Ca2+-dependent K+ channels (SKCa channels), did not affect Δk; K,o. Fifth, tolbutamide (800 µM), an inhibitor of KATP channels, reduced Δk; K,o by about 23%. Sixth, Ba2+, a blocker of most K+ channels, did not preclude the caffeine-induced Δk; K,o. Seventh, omitting Na+ from the external medium reduced Δk; K,o by about 40%. Eight, amiloride (5 mM) decreased Δk; K,o by 65%. It is concluded that the caffeine-induced rise of [Ca2+]i increases K+ efflux, through the activation of: (1) two channels (BKCa and KATP) and (2) an external Na+-dependent amiloride-sensitive process.
Centro de Investigaciones Cardiovasculares - Materia
-
Ciencias Médicas
Caffeine
Calcium
Efflux
Frog
Potassium
Skeletal muscle - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- http://creativecommons.org/licenses/by/4.0/
- Repositorio
- Institución
- Universidad Nacional de La Plata
- OAI Identificador
- oai:sedici.unlp.edu.ar:10915/145104
Ver los metadatos del registro completo
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Effect of caffeine on K+ efflux in frog skeletal muscleVenosa, Roque AlbertoHoya, ArturoCiencias MédicasCaffeineCalciumEffluxFrogPotassiumSkeletal muscleThe exposure of frog skeletal muscle to caffeine (3–4 mM) generates an increase of the K+ (42K+) efflux rate coefficient (k; K,o) which exhibits the following characteristics. First it is promoted by the rise in cytosolic Ca2+ ([Ca2+]i), because the effect is mimicked by ionomycin (1.25 µM), a Ca2+ ionophore. Second, the inhibition of caffeine-induced Ca2+ release from the sarcoplasmic reticulum (SR) by 40 µM tetracaine significantly reduced the increase in k; K,o (Δk; K,o). Third, charybdotoxin (23 nM), a blocker of the large-conductance Ca2+-dependent K+ channels (BKCa channels) reduced Δk; K,o by 22%. Fourth, apamin (10 nM), a blocker of the small-conductance Ca2+-dependent K+ channels (SKCa channels), did not affect Δk; K,o. Fifth, tolbutamide (800 µM), an inhibitor of KATP channels, reduced Δk; K,o by about 23%. Sixth, Ba2+, a blocker of most K+ channels, did not preclude the caffeine-induced Δk; K,o. Seventh, omitting Na+ from the external medium reduced Δk; K,o by about 40%. Eight, amiloride (5 mM) decreased Δk; K,o by 65%. It is concluded that the caffeine-induced rise of [Ca2+]i increases K+ efflux, through the activation of: (1) two channels (BKCa and KATP) and (2) an external Na+-dependent amiloride-sensitive process.Centro de Investigaciones Cardiovasculares1999-01-18info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf417-422http://sedici.unlp.edu.ar/handle/10915/145104enginfo:eu-repo/semantics/altIdentifier/issn/0031-6768info:eu-repo/semantics/altIdentifier/issn/1432-2013info:eu-repo/semantics/altIdentifier/doi/10.1007/s004240050796info:eu-repo/semantics/altIdentifier/pmid/9914398info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/4.0/Creative Commons Attribution 4.0 International (CC BY 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:32:12Zoai:sedici.unlp.edu.ar:10915/145104Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:32:13.256SEDICI (UNLP) - Universidad Nacional de La Platafalse |
dc.title.none.fl_str_mv |
Effect of caffeine on K+ efflux in frog skeletal muscle |
title |
Effect of caffeine on K+ efflux in frog skeletal muscle |
spellingShingle |
Effect of caffeine on K+ efflux in frog skeletal muscle Venosa, Roque Alberto Ciencias Médicas Caffeine Calcium Efflux Frog Potassium Skeletal muscle |
title_short |
Effect of caffeine on K+ efflux in frog skeletal muscle |
title_full |
Effect of caffeine on K+ efflux in frog skeletal muscle |
title_fullStr |
Effect of caffeine on K+ efflux in frog skeletal muscle |
title_full_unstemmed |
Effect of caffeine on K+ efflux in frog skeletal muscle |
title_sort |
Effect of caffeine on K+ efflux in frog skeletal muscle |
dc.creator.none.fl_str_mv |
Venosa, Roque Alberto Hoya, Arturo |
author |
Venosa, Roque Alberto |
author_facet |
Venosa, Roque Alberto Hoya, Arturo |
author_role |
author |
author2 |
Hoya, Arturo |
author2_role |
author |
dc.subject.none.fl_str_mv |
Ciencias Médicas Caffeine Calcium Efflux Frog Potassium Skeletal muscle |
topic |
Ciencias Médicas Caffeine Calcium Efflux Frog Potassium Skeletal muscle |
dc.description.none.fl_txt_mv |
The exposure of frog skeletal muscle to caffeine (3–4 mM) generates an increase of the K+ (42K+) efflux rate coefficient (k; K,o) which exhibits the following characteristics. First it is promoted by the rise in cytosolic Ca2+ ([Ca2+]i), because the effect is mimicked by ionomycin (1.25 µM), a Ca2+ ionophore. Second, the inhibition of caffeine-induced Ca2+ release from the sarcoplasmic reticulum (SR) by 40 µM tetracaine significantly reduced the increase in k; K,o (Δk; K,o). Third, charybdotoxin (23 nM), a blocker of the large-conductance Ca2+-dependent K+ channels (BKCa channels) reduced Δk; K,o by 22%. Fourth, apamin (10 nM), a blocker of the small-conductance Ca2+-dependent K+ channels (SKCa channels), did not affect Δk; K,o. Fifth, tolbutamide (800 µM), an inhibitor of KATP channels, reduced Δk; K,o by about 23%. Sixth, Ba2+, a blocker of most K+ channels, did not preclude the caffeine-induced Δk; K,o. Seventh, omitting Na+ from the external medium reduced Δk; K,o by about 40%. Eight, amiloride (5 mM) decreased Δk; K,o by 65%. It is concluded that the caffeine-induced rise of [Ca2+]i increases K+ efflux, through the activation of: (1) two channels (BKCa and KATP) and (2) an external Na+-dependent amiloride-sensitive process. Centro de Investigaciones Cardiovasculares |
description |
The exposure of frog skeletal muscle to caffeine (3–4 mM) generates an increase of the K+ (42K+) efflux rate coefficient (k; K,o) which exhibits the following characteristics. First it is promoted by the rise in cytosolic Ca2+ ([Ca2+]i), because the effect is mimicked by ionomycin (1.25 µM), a Ca2+ ionophore. Second, the inhibition of caffeine-induced Ca2+ release from the sarcoplasmic reticulum (SR) by 40 µM tetracaine significantly reduced the increase in k; K,o (Δk; K,o). Third, charybdotoxin (23 nM), a blocker of the large-conductance Ca2+-dependent K+ channels (BKCa channels) reduced Δk; K,o by 22%. Fourth, apamin (10 nM), a blocker of the small-conductance Ca2+-dependent K+ channels (SKCa channels), did not affect Δk; K,o. Fifth, tolbutamide (800 µM), an inhibitor of KATP channels, reduced Δk; K,o by about 23%. Sixth, Ba2+, a blocker of most K+ channels, did not preclude the caffeine-induced Δk; K,o. Seventh, omitting Na+ from the external medium reduced Δk; K,o by about 40%. Eight, amiloride (5 mM) decreased Δk; K,o by 65%. It is concluded that the caffeine-induced rise of [Ca2+]i increases K+ efflux, through the activation of: (1) two channels (BKCa and KATP) and (2) an external Na+-dependent amiloride-sensitive process. |
publishDate |
1999 |
dc.date.none.fl_str_mv |
1999-01-18 |
dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Articulo http://purl.org/coar/resource_type/c_6501 info:ar-repo/semantics/articulo |
format |
article |
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publishedVersion |
dc.identifier.none.fl_str_mv |
http://sedici.unlp.edu.ar/handle/10915/145104 |
url |
http://sedici.unlp.edu.ar/handle/10915/145104 |
dc.language.none.fl_str_mv |
eng |
language |
eng |
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info:eu-repo/semantics/altIdentifier/issn/0031-6768 info:eu-repo/semantics/altIdentifier/issn/1432-2013 info:eu-repo/semantics/altIdentifier/doi/10.1007/s004240050796 info:eu-repo/semantics/altIdentifier/pmid/9914398 |
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info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International (CC BY 4.0) |
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openAccess |
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http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International (CC BY 4.0) |
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