Dantrolene, like fatigue, has a length-dependent effect on submaximal force–length relationships of rat gastrocnemius muscle.
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| Title: | Dantrolene, like fatigue, has a length-dependent effect on submaximal force–length relationships of rat gastrocnemius muscle. |
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| Authors: | MacNaughton, M. B., Campbell, J. J., MacIntosh, B. R. |
| Source: | Acta Physiologica. Mar2007, Vol. 189 Issue 3, p271-278. 8p. 6 Graphs. |
| Subjects: | Dantrolene, Mental depression, Fatigue (Physiology), Cytoplasmic filaments, Intravenous therapy, Propene |
| Abstract: | Aim: Fatigue is length-dependent; relative active force depression is greater when measured at short lengths than at long lengths. Several unsatisfactory mechanisms have been proposed to explain this length dependence of fatigue, including: damaged myofilaments, stretch of ‘in-series’ structures, impaired t-tubule conduction and reduced intensity of activation. Dantrolene targets the ryanodine receptors, inhibiting stimulation-induced release of Ca2+. The purpose of this study was to determine if the force depression caused by dantrolene treatment also has a length dependence. Methods: Submaximal (single-pulse, double-pulse and 50 Hz stimulation) active force–length relationships were obtained from the medial gastrocnemius muscle of anaesthetized rats, before and after intravenous injection with dantrolene dissolved in propylene glycol. Results: Dantrolene treatment was sufficient to reduce twitch amplitude by 25%. Similar to the consequences of repetitive stimulation, dantrolene treatment caused the same decrease in absolute active force across a broad range of test lengths, for twitch, double-pulse and 50 Hz contractions. Considering that active force is smaller at short lengths than at long lengths, this similar absolute force decrease represents a greater relative decrease at short lengths. Clearly, there is a length-dependent impact of attenuated Ca2+ release by dantrolene on relative active force. Conclusion: This study demonstrates that there is a length dependence of force depression associated with decreased Ca2+ release due to dantrolene treatment; therefore, if fatigue is due to decreased Ca2+ release, then additional length-dependent mechanisms are not required to explain the reported length dependence of force depression. [ABSTRACT FROM AUTHOR] |
| Copyright of Acta Physiologica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Psychology and Behavioral Sciences Collection |
| FullText | Links: – Type: pdflink Text: Availability: 0 |
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| Header | DbId: pbh DbLabel: Psychology and Behavioral Sciences Collection An: 23972406 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Dantrolene, like fatigue, has a length-dependent effect on submaximal force–length relationships of rat gastrocnemius muscle. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22MacNaughton%2C+M%2E+B%2E%22">MacNaughton, M. B.</searchLink><br /><searchLink fieldCode="AR" term="%22Campbell%2C+J%2E+J%2E%22">Campbell, J. J.</searchLink><br /><searchLink fieldCode="AR" term="%22MacIntosh%2C+B%2E+R%2E%22">MacIntosh, B. R.</searchLink> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Acta+Physiologica%22">Acta Physiologica</searchLink>. Mar2007, Vol. 189 Issue 3, p271-278. 8p. 6 Graphs. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Dantrolene%22">Dantrolene</searchLink><br /><searchLink fieldCode="DE" term="%22Mental+depression%22">Mental depression</searchLink><br /><searchLink fieldCode="DE" term="%22Fatigue+%28Physiology%29%22">Fatigue (Physiology)</searchLink><br /><searchLink fieldCode="DE" term="%22Cytoplasmic+filaments%22">Cytoplasmic filaments</searchLink><br /><searchLink fieldCode="DE" term="%22Intravenous+therapy%22">Intravenous therapy</searchLink><br /><searchLink fieldCode="DE" term="%22Propene%22">Propene</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Aim: Fatigue is length-dependent; relative active force depression is greater when measured at short lengths than at long lengths. Several unsatisfactory mechanisms have been proposed to explain this length dependence of fatigue, including: damaged myofilaments, stretch of ‘in-series’ structures, impaired t-tubule conduction and reduced intensity of activation. Dantrolene targets the ryanodine receptors, inhibiting stimulation-induced release of Ca2+. The purpose of this study was to determine if the force depression caused by dantrolene treatment also has a length dependence. Methods: Submaximal (single-pulse, double-pulse and 50 Hz stimulation) active force–length relationships were obtained from the medial gastrocnemius muscle of anaesthetized rats, before and after intravenous injection with dantrolene dissolved in propylene glycol. Results: Dantrolene treatment was sufficient to reduce twitch amplitude by 25%. Similar to the consequences of repetitive stimulation, dantrolene treatment caused the same decrease in absolute active force across a broad range of test lengths, for twitch, double-pulse and 50 Hz contractions. Considering that active force is smaller at short lengths than at long lengths, this similar absolute force decrease represents a greater relative decrease at short lengths. Clearly, there is a length-dependent impact of attenuated Ca2+ release by dantrolene on relative active force. Conclusion: This study demonstrates that there is a length dependence of force depression associated with decreased Ca2+ release due to dantrolene treatment; therefore, if fatigue is due to decreased Ca2+ release, then additional length-dependent mechanisms are not required to explain the reported length dependence of force depression. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Acta Physiologica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1111/j.1748-1716.2006.01645.x Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 8 StartPage: 271 Subjects: – SubjectFull: Dantrolene Type: general – SubjectFull: Mental depression Type: general – SubjectFull: Fatigue (Physiology) Type: general – SubjectFull: Cytoplasmic filaments Type: general – SubjectFull: Intravenous therapy Type: general – SubjectFull: Propene Type: general Titles: – TitleFull: Dantrolene, like fatigue, has a length-dependent effect on submaximal force–length relationships of rat gastrocnemius muscle. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: MacNaughton, M. B. – PersonEntity: Name: NameFull: Campbell, J. J. – PersonEntity: Name: NameFull: MacIntosh, B. R. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 03 Text: Mar2007 Type: published Y: 2007 Identifiers: – Type: issn-print Value: 17481708 Numbering: – Type: volume Value: 189 – Type: issue Value: 3 Titles: – TitleFull: Acta Physiologica Type: main |
| ResultId | 1 |
