Synchronous in situ ATPase activity, mechanics, and Ca2+ sensitivity of human and porcine myocardium.
Flash-frozen myocardium samples provide a valuable means of correlating clinical cardiomyopathies with abnormalities in sarcomeric contractile and biochemical parameters. We examined flash-frozen left-ventricle human cardiomyocyte bundles from healthy donors to determine control parameters for isome...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Journal article |
| Language: | English |
| Published: |
2009
|
| _version_ | 1826274501403344896 |
|---|---|
| author | Griffiths, P Isackson, H Pelc, R Redwood, C Funari, S Watkins, H Ashley, C |
| author_facet | Griffiths, P Isackson, H Pelc, R Redwood, C Funari, S Watkins, H Ashley, C |
| author_sort | Griffiths, P |
| collection | OXFORD |
| description | Flash-frozen myocardium samples provide a valuable means of correlating clinical cardiomyopathies with abnormalities in sarcomeric contractile and biochemical parameters. We examined flash-frozen left-ventricle human cardiomyocyte bundles from healthy donors to determine control parameters for isometric tension (P(o)) development and Ca(2+) sensitivity, while simultaneously measuring actomyosin ATPase activity in situ by a fluorimetric technique. P(o) was 17 kN m(-2) and pCa(50%) was 5.99 (28 degrees C, I = 130 mM). ATPase activity increased linearly with tension to 132 muM s(-1). To determine the influence of flash-freezing, we compared the same parameters in both glycerinated and flash-frozen porcine left-ventricle trabeculae. P(o) in glycerinated porcine myocardium was 25 kN m(-2), and maximum ATPase activity was 183 microM s(-1). In flash-frozen porcine myocardium, P(o) was 16 kN m(-2) and maximum ATPase activity was 207 microM s(-1). pCa(50%) was 5.77 in the glycerinated and 5.83 in the flash-frozen sample. Both passive and active stiffness of flash-frozen porcine myocardium were lower than for glycerinated tissue and similar to the human samples. Although lower stiffness and isometric tension development may indicate flash-freezing impairment of axial force transmission, we cannot exclude variability between samples as the cause. ATPase activity and pCa(50%) were unaffected by flash-freezing. The lower ATPase activity measured in human tissue suggests a slower actomyosin turnover by the contractile proteins. |
| first_indexed | 2024-03-06T22:44:23Z |
| format | Journal article |
| id | oxford-uuid:5ca93182-6375-4efc-bd2e-0b3e2a5ffd60 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T22:44:23Z |
| publishDate | 2009 |
| record_format | dspace |
| spelling | oxford-uuid:5ca93182-6375-4efc-bd2e-0b3e2a5ffd602022-03-26T17:29:33ZSynchronous in situ ATPase activity, mechanics, and Ca2+ sensitivity of human and porcine myocardium.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:5ca93182-6375-4efc-bd2e-0b3e2a5ffd60EnglishSymplectic Elements at Oxford2009Griffiths, PIsackson, HPelc, RRedwood, CFunari, SWatkins, HAshley, CFlash-frozen myocardium samples provide a valuable means of correlating clinical cardiomyopathies with abnormalities in sarcomeric contractile and biochemical parameters. We examined flash-frozen left-ventricle human cardiomyocyte bundles from healthy donors to determine control parameters for isometric tension (P(o)) development and Ca(2+) sensitivity, while simultaneously measuring actomyosin ATPase activity in situ by a fluorimetric technique. P(o) was 17 kN m(-2) and pCa(50%) was 5.99 (28 degrees C, I = 130 mM). ATPase activity increased linearly with tension to 132 muM s(-1). To determine the influence of flash-freezing, we compared the same parameters in both glycerinated and flash-frozen porcine left-ventricle trabeculae. P(o) in glycerinated porcine myocardium was 25 kN m(-2), and maximum ATPase activity was 183 microM s(-1). In flash-frozen porcine myocardium, P(o) was 16 kN m(-2) and maximum ATPase activity was 207 microM s(-1). pCa(50%) was 5.77 in the glycerinated and 5.83 in the flash-frozen sample. Both passive and active stiffness of flash-frozen porcine myocardium were lower than for glycerinated tissue and similar to the human samples. Although lower stiffness and isometric tension development may indicate flash-freezing impairment of axial force transmission, we cannot exclude variability between samples as the cause. ATPase activity and pCa(50%) were unaffected by flash-freezing. The lower ATPase activity measured in human tissue suggests a slower actomyosin turnover by the contractile proteins. |
| spellingShingle | Griffiths, P Isackson, H Pelc, R Redwood, C Funari, S Watkins, H Ashley, C Synchronous in situ ATPase activity, mechanics, and Ca2+ sensitivity of human and porcine myocardium. |
| title | Synchronous in situ ATPase activity, mechanics, and Ca2+ sensitivity of human and porcine myocardium. |
| title_full | Synchronous in situ ATPase activity, mechanics, and Ca2+ sensitivity of human and porcine myocardium. |
| title_fullStr | Synchronous in situ ATPase activity, mechanics, and Ca2+ sensitivity of human and porcine myocardium. |
| title_full_unstemmed | Synchronous in situ ATPase activity, mechanics, and Ca2+ sensitivity of human and porcine myocardium. |
| title_short | Synchronous in situ ATPase activity, mechanics, and Ca2+ sensitivity of human and porcine myocardium. |
| title_sort | synchronous in situ atpase activity mechanics and ca2 sensitivity of human and porcine myocardium |
| work_keys_str_mv | AT griffithsp synchronousinsituatpaseactivitymechanicsandca2sensitivityofhumanandporcinemyocardium AT isacksonh synchronousinsituatpaseactivitymechanicsandca2sensitivityofhumanandporcinemyocardium AT pelcr synchronousinsituatpaseactivitymechanicsandca2sensitivityofhumanandporcinemyocardium AT redwoodc synchronousinsituatpaseactivitymechanicsandca2sensitivityofhumanandporcinemyocardium AT funaris synchronousinsituatpaseactivitymechanicsandca2sensitivityofhumanandporcinemyocardium AT watkinsh synchronousinsituatpaseactivitymechanicsandca2sensitivityofhumanandporcinemyocardium AT ashleyc synchronousinsituatpaseactivitymechanicsandca2sensitivityofhumanandporcinemyocardium |