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dc.contributor.authorSarbjit-Singh, Sahib S.
dc.contributor.authorMatthews, Hugh R.
dc.contributor.authorHuang, Christopher L.-H.
dc.date.accessioned2021-02-09T16:32:48Z
dc.date.available2021-02-09T16:32:48Z
dc.date.issued2020-02-10
dc.date.submitted2019-08-21
dc.identifier.others41598-020-59196-9
dc.identifier.other59196
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/317386
dc.description.abstractAbstract: We investigated effects of the ryanodine receptor (RyR) modulator caffeine on Na+ current (INa) activation and inactivation in intact loose-patch clamped murine skeletal muscle fibres subject to a double pulse procedure. INa activation was examined using 10-ms depolarising, V1, steps to varying voltages 0–80 mV positive to resting membrane potential. The dependence of the subsequent, INa inactivation on V1 was examined by superimposed, V2, steps to a fixed depolarising voltage. Current-voltage activation and inactivation curves indicated that adding 0.5 and 2 mM caffeine prior to establishing the patch seal respectively produced decreased (within 1 min) and increased (after ~2 min) peak INa followed by its recovery to pretreatment levels (after ~40 and ~30 min respectively). These changes accompanied negative shifts in the voltage dependence of INa inactivation (within 10 min) and subsequent superimposed positive activation and inactivation shifts, following 0.5 mM caffeine challenge. In contrast, 2 mM caffeine elicited delayed negative shifts in both activation and inactivation. These effects were abrogated if caffeine was added after establishing the patch seal or with RyR block by 10 μM dantrolene. These effects precisely paralleled previous reports of persistently (~10 min) increased cytosolic [Ca2+] with 0.5 mM, and an early peak rapidly succeeded by persistently reduced [Ca2+] likely reflecting gradual RyR inactivation with ≥1.0 mM caffeine. The latter findings suggested inhibitory effects of even resting cytosolic [Ca2+] on INa. They suggest potentially physiologically significant negative feedback regulation of RyR activity on Nav1.4 properties through increased or decreased local cytosolic [Ca2+], Ca2+-calmodulin and FKBP12.
dc.languageen
dc.publisherNature Publishing Group UK
dc.rightsAttribution 4.0 International (CC BY 4.0)en
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/en
dc.subjectArticle
dc.subject/631/443
dc.subject/692/617
dc.subjectarticle
dc.titleRyanodine receptor modulation by caffeine challenge modifies Na + current properties in intact murine skeletal muscle fibres
dc.typeArticle
dc.date.updated2021-02-09T16:32:47Z
prism.issueIdentifier1
prism.publicationNameScientific Reports
prism.volume10
dc.identifier.doi10.17863/CAM.64499
dcterms.dateAccepted2020-01-06
rioxxterms.versionofrecord10.1038/s41598-020-59196-9
rioxxterms.versionVoR
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/
dc.identifier.eissn2045-2322


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Attribution 4.0 International (CC BY 4.0)
Except where otherwise noted, this item's licence is described as Attribution 4.0 International (CC BY 4.0)