Elementary Ca2+ release events in mammalian skeletal muscle: Effects of the anaesthetic drug thiopental

Wegner, F. V., Both, M., Fink, R. H. A. and Friedrich, O. (2006) Elementary Ca2+ release events in mammalian skeletal muscle: Effects of the anaesthetic drug thiopental. Journal of Muscle Research And Cell Motility, 27 5-7: 315-326. doi:10.1007/s10974-006-9092-3


Author Wegner, F. V.
Both, M.
Fink, R. H. A.
Friedrich, O.
Title Elementary Ca2+ release events in mammalian skeletal muscle: Effects of the anaesthetic drug thiopental
Formatted title
Elementary Ca2+ release events in mammalian skeletal muscle: Effects of the anaesthetic drug thiopental
Journal name Journal of Muscle Research And Cell Motility   Check publisher's open access policy
ISSN 0142-4319
1573-2657
Publication date 2006-05
Sub-type Article (original research)
DOI 10.1007/s10974-006-9092-3
Volume 27
Issue 5-7
Start page 315
End page 326
Total pages 12
Editor C. C. Ashley
D. J. Manstein
M. Gautel
Place of publication London, U.K.
Publisher Kluwer
Language eng
Subject 0601 Biochemistry and Cell Biology
Formatted abstract
We examined the effect of clinically relevant doses of thiopental (10-100 μM) on Ca2+ release from the sarcoplasmic reticulum of chemically skinned skeletal muscle fibres of the mouse. Elementary Ca2+ release events (ECRE) were recorded with confocal microscopy and were detected and analysed by an automated algorithm. Thiopental at 25 μM evoked a marked increase in ECRE frequency (events/100 μm/s) from 0.64 ± 0.32 to 1.56 ± 0.38 (P < 0.001). Incubation with 5 μM ryanodine significantly reduced spontaneous and evoked ECRE frequencies to 0.08 ± 0.08 (P < 0.001) and 0.39 ± 0.25 (25 μM thiopental, P < 0.001) respectively. Thiopental-evoked ECRE show different morphological characteristics compared to spontaneous events. Maximum relative amplitudes (ΔF/F 0) max and spatial width (full width at half maximum) of the events were substantially increased. Full duration at half maximum was increased and some very long events (200 ms compared to ∼30 ms standard) were produced. The rise times as an indicator of the channel open time were slightly increased. Furthermore, the occurrence of repetitive ECRE was observed. These events, in contrast to previous observations in amphibian skeletal muscle fibres, displayed a multitude of different release patterns. In particular, a repetitive ECRE mode with successively decaying amplitudes was identified and the inter-event intervals were analysed. Estimation of the underlying Ca2+ release current suggests that during repetitive events with a decaying amplitude a decreasing amount of Ca2+ was released within the individual release event. Possible underlying mechanisms are discussed. In summary, thiopental seems to be a potent RyR1 agonist and substantially alters the gating mechanisms of RyR Ca2+ release channel clusters already in clinically relevant doses, i.e. doses administered during general anaesthesia.
© Springer Science+Business Media B.V. 2006.
Keyword Calcium sparks
Elementary calcium release events
Skeletal muscle
Thiopental
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Biomedical Sciences Publications
 
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