Force–frequency and force–length properties in skeletal muscle following unilateral focal ischaemic insult in a rat model.
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| Title: | Force–frequency and force–length properties in skeletal muscle following unilateral focal ischaemic insult in a rat model. |
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| Authors: | Dormer, G. N., Teskey, G. C., MacIntosh, B. R. |
| Source: | Acta Physiologica. Nov2009, Vol. 197 Issue 3, p227-239. 13p. 1 Color Photograph, 3 Charts, 9 Graphs. |
| Subjects: | Rats, Ischemia, Neocortex, Pyramidal tract, Neurons |
| Abstract: | Aim: Our purpose was to quantify skeletal muscle properties following unilateral focal ischaemic insult (stroke) in a rat model. Methods: Male rats were divided into two groups: stroke and 2 weeks recovery ( n = 8) and control group ( n = 7). Stroke was induced in the area of the motor neocortex containing hind limb corticospinal neurones. Contractile properties of the medial gastrocnemius muscle were measured in situ in both limbs. Force–length and force–frequency properties were measured before and 35 min after 5 min fatiguing stimulation. Results: Stroke resulted in bilateral tetanic fade during 200 Hz stimulation. When normalized to 100 Hz contractions, force at 200 Hz was 95.4 ± 0.9% for the paretic muscles, 96.7 ± 1.7% for non-paretic muscles and 102.2 ± 1.0% for muscles of control rats ( P = 0.006). Prior to fatiguing contractions, there was no difference in the length dependence of force. During repetitive contractions, active force fell significantly to 19 ± 4 and 25 ± 5% of initial force in paretic and non-paretic muscles of animals with a stroke respectively. In control animals active force fell to 37 ± 5%. During repetitive contractions, fusion index increased in muscles of stroke animals to 1.0 ± 0 but in control animals it was 0.95 ± 0.02. There was selective force depression at short lengths for fatigued paretic muscle (significant difference at muscle lengths less than reference length −2 mm). Conclusion: The tetanic fade at high stimulation frequencies indicates that there may be activation failure following focal ischaemic insult. The greater magnitude of fatigue and selective depression at short lengths following repetitive contractions should be investigated further. [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: 44499554 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Force–frequency and force–length properties in skeletal muscle following unilateral focal ischaemic insult in a rat model. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Dormer%2C+G%2E+N%2E%22">Dormer, G. N.</searchLink><br /><searchLink fieldCode="AR" term="%22Teskey%2C+G%2E+C%2E%22">Teskey, G. C.</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>. Nov2009, Vol. 197 Issue 3, p227-239. 13p. 1 Color Photograph, 3 Charts, 9 Graphs. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Rats%22">Rats</searchLink><br /><searchLink fieldCode="DE" term="%22Ischemia%22">Ischemia</searchLink><br /><searchLink fieldCode="DE" term="%22Neocortex%22">Neocortex</searchLink><br /><searchLink fieldCode="DE" term="%22Pyramidal+tract%22">Pyramidal tract</searchLink><br /><searchLink fieldCode="DE" term="%22Neurons%22">Neurons</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Aim: Our purpose was to quantify skeletal muscle properties following unilateral focal ischaemic insult (stroke) in a rat model. Methods: Male rats were divided into two groups: stroke and 2 weeks recovery ( n = 8) and control group ( n = 7). Stroke was induced in the area of the motor neocortex containing hind limb corticospinal neurones. Contractile properties of the medial gastrocnemius muscle were measured in situ in both limbs. Force–length and force–frequency properties were measured before and 35 min after 5 min fatiguing stimulation. Results: Stroke resulted in bilateral tetanic fade during 200 Hz stimulation. When normalized to 100 Hz contractions, force at 200 Hz was 95.4 ± 0.9% for the paretic muscles, 96.7 ± 1.7% for non-paretic muscles and 102.2 ± 1.0% for muscles of control rats ( P = 0.006). Prior to fatiguing contractions, there was no difference in the length dependence of force. During repetitive contractions, active force fell significantly to 19 ± 4 and 25 ± 5% of initial force in paretic and non-paretic muscles of animals with a stroke respectively. In control animals active force fell to 37 ± 5%. During repetitive contractions, fusion index increased in muscles of stroke animals to 1.0 ± 0 but in control animals it was 0.95 ± 0.02. There was selective force depression at short lengths for fatigued paretic muscle (significant difference at muscle lengths less than reference length −2 mm). Conclusion: The tetanic fade at high stimulation frequencies indicates that there may be activation failure following focal ischaemic insult. The greater magnitude of fatigue and selective depression at short lengths following repetitive contractions should be investigated further. [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.1748-1716.2009.02001.x Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 13 StartPage: 227 Subjects: – SubjectFull: Rats Type: general – SubjectFull: Ischemia Type: general – SubjectFull: Neocortex Type: general – SubjectFull: Pyramidal tract Type: general – SubjectFull: Neurons Type: general Titles: – TitleFull: Force–frequency and force–length properties in skeletal muscle following unilateral focal ischaemic insult in a rat model. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Dormer, G. N. – PersonEntity: Name: NameFull: Teskey, G. C. – PersonEntity: Name: NameFull: MacIntosh, B. R. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 11 Text: Nov2009 Type: published Y: 2009 Identifiers: – Type: issn-print Value: 17481708 Numbering: – Type: volume Value: 197 – Type: issue Value: 3 Titles: – TitleFull: Acta Physiologica Type: main |
| ResultId | 1 |
