Sökning: L773:0031 6768 OR L773:1432 2013
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Paradoxical decreas...
Paradoxical decrease in cytosolic calcium with increasing depolarization by potassium in guinea-pig mesotubarium smooth muscle
- Artikel/kapitelEngelska1992
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LIBRIS-ID:oai:lup.lub.lu.se:a828fe47-3869-4d2a-9e52-cf4280bdc038
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https://lup.lub.lu.se/record/1106622URI
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https://doi.org/10.1007/BF00374616DOI
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Språk:engelska
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Sammanfattning på:engelska
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Ämneskategori:art swepub-publicationtype
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Ämneskategori:ref swepub-contenttype
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The free intracellular Ca2+ concentration ([Ca2+]i) was measured simultaneously with isometric force in strips of guinea-pig mesotubarium using the Fura-2 technique. [Ca2+]i and force were maximal at a relatively low (30 mM) concentration of extracellular K+ ([K+]o), and declined at 90 and 140 mM K+. Plateau values of both [Ca2+]i and force were higher in the presence of 5.10(-6) M ryanodine, indicating that the sarcoplasmic reticulum (SR) contributes to the decline with depolarization. Force and [Ca2+]i at 90 mM K+ were both lower then the high-K+ solution was applied after a period in 30 mM K+ than after a period in normal solution (5.9 mM K+), consistent with inactivation of Ca2+ channels during prolonged depolarization. Addition of carbachol to the depolarized muscle caused a maintained increase in force without maintained increase in [Ca2+]i. We conclude that the decrease in force at increased [K+]o (the "calcium-potassium paradox") is due to a membrane-potential-mediated decrease in [Ca2+]i and, to a lesser extent, to desensitization of the contractile-regulatory apparatus to Ca2+.
Ämnesord och genrebeteckningar
Biuppslag (personer, institutioner, konferenser, titlar ...)
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Himpens, B
(författare)
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Droogmans, G
(författare)
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Hellstrand, PerLund University,Lunds universitet,Kärlfysiologi,Forskargrupper vid Lunds universitet,Vascular Physiology,Lund University Research Groups(Swepub:lu)mphy-phe
(författare)
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Somlyo, A P
(författare)
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KärlfysiologiForskargrupper vid Lunds universitet
(creator_code:org_t)
Sammanhörande titlar
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Ingår i:Pflügers Archiv420:5-6, s. 428-4330031-6768
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