In vitro contractile responses and contracture testing of skeletal muscle from Quarter Horses with exertional rhabdomyolysis.
Abstract: To determine whether increased sensitivity to pharmacologic agents was a general property of equine exertional myopathies, including polysaccharide storage myopathy (PSSM) in Quarter Horses. Methods: 5 adult Quarter Horses with exertional rhabdomyolysis and abnormal polysaccharide accumulation in skeletal muscle and 4 clinically normal adult Quarter or Quarter-type horses. Methods: Twitch time course measurements and contracture responses to various concentrations of caffeine and halothane for small bundles of intact external intercostal muscle fibers were measured in all horses. Results: Caffeine contracture threshold of muscles from Quarter Horses with PSSM was not different from that of clinically normal horses (5 mM in both groups). Muscles from horses with PSSM and from clinically normal horses did not have contracture in response to up to 2% halothane. Conclusions: Results were in contrast to the increased sensitivity to caffeine and halothane for muscles from Thoroughbreds with recurrent exertional rhabdomyolysis (RER). Although clinical signs of muscular stiffness after exercise are similar between Quarter Horses with PSSM and Thoroughbreds with RER, these breeds appear to have 2 distinct myopathies with different pathophysiologic bases. Unlike RER in Thoroughbreds, PSSM in Quarter Horses does not appear to be accompanied by a defect in regulation of muscle contraction.
Publication Date: 1999-06-22 PubMed ID: 10376892
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- Journal Article
Summary
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The research article is about a study conducted on Quarter Horses with a muscle disease known as exertional rhabdomyolysis (ERM), to determine whether they display heightened sensitivity to certain pharmacological agents. The researchers discovered distinct pathophysiological bases for the ERM conditions among different breeds like Quarter Horses and Thoroughbreds, indicating different underlying causes.
Study Objective
- The main aim of the research was to find out if increased sensitivity to pharmacologic agents was a common feature of equine exertional myopathies. These are muscle disorders found in horses and include polysaccharide storage myopathy (PSSM) which is common in Quarter Horses.
Methods Used
- The study was conducted on five adult Quarter Horses suffering from exertional rhabdomyolysis and abnormal polysaccharide accumulation in skeletal muscles. Four clinically normal adult Quarter or Quarter-type horses were also included as a control group.
- Measurements of twitch time course and contracture responses to varying concentrations of caffeine and halothane were taken for intact external intercostal muscle fibers in all horses involved in the study.
Findings
- The threshold for caffeine contracture (muscle contraction response) was observed to be the same (5 mM) for both PSSM-afflicted Quarter Horses and healthy ones.
- No muscle contraction response (contracture) was observed in either group when exposed to up to 2% halothane.
Conclusion
- The results of this study contrasted with the increased susceptibility to caffeine and halothane exhibited by Thoroughbreds with recurrent exertional rhabdomyolysis (RER). Despite similar symptoms, these findings suggest distinct myopathies in Quarter Horses with PSSM and Thoroughbreds with RER, with different pathophysiological bases.
- Unlike RER in Thoroughbreds, PSSM in Quarter Horses did not appear to come with a defect in the regulation of muscle contraction.
Cite This Article
APA
Lentz LR, Valberg SJ, Mickelson JR, Gallant EM.
(1999).
In vitro contractile responses and contracture testing of skeletal muscle from Quarter Horses with exertional rhabdomyolysis.
Am J Vet Res, 60(6), 684-688.
Publication
Researcher Affiliations
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, St Paul 55108, USA.
MeSH Terms
- Animals
- Caffeine / pharmacology
- Contracture / etiology
- Contracture / pathology
- Contracture / physiopathology
- Contracture / veterinary
- Horse Diseases / etiology
- Horse Diseases / pathology
- Horse Diseases / physiopathology
- Horses
- Muscle Contraction / drug effects
- Muscle, Skeletal / drug effects
- Muscle, Skeletal / pathology
- Muscle, Skeletal / physiopathology
- Physical Conditioning, Animal / adverse effects
- Rhabdomyolysis / etiology
- Rhabdomyolysis / pathology
- Rhabdomyolysis / physiopathology
- Rhabdomyolysis / veterinary
Citations
This article has been cited 4 times.- Autry JM, Svensson B, Carlson SF, Chen Z, Cornea RL, Thomas DD, Valberg SJ. Sarcoplasmic Reticulum from Horse Gluteal Muscle Is Poised for Enhanced Calcium Transport. Vet Sci 2021 Nov 23;8(12).
- Autry JM, Karim CB, Cocco M, Carlson SF, Thomas DD, Valberg SJ. Purification of sarcoplasmic reticulum vesicles from horse gluteal muscle. Anal Biochem 2020 Dec 1;610:113965.
- Fernandez-Fuente M, Terracciano CM, Martin-Duque P, Brown SC, Vassaux G, Piercy RJ. Calcium homeostasis in myogenic differentiation factor 1 (MyoD)-transformed, virally-transduced, skin-derived equine myotubes. PLoS One 2014;9(8):e105971.
- Isgren CM, Upjohn MM, Fernandez-Fuente M, Massey C, Pollott G, Verheyen KL, Piercy RJ. Epidemiology of exertional rhabdomyolysis susceptibility in standardbred horses reveals associated risk factors and underlying enhanced performance. PLoS One 2010 Jul 14;5(7):e11594.
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