Journal article
Development and cardiac contractility : Cardiac troponin T isoforms and cytosolic calcium in rabbit
Pediatric research, v 60(3), pp 276-281
01 Sep 2006
PMID: 16857772
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Cardiac contractility depends on calcium sensitivity of the myofilaments and cytosolic free calcium concentration ([Ca2+]i) during activation. During development, the cardiac troponin T isoform cTnT1 is replaced by shorter cTnT isoforms, including cTnT4, and changes occur in other myofibrillar proteins and in calcium regulation. We expressed rabbit recombinant (r)cTnT1 and rcTnT4 in Spodoptera frugiperda cells and determined their effect on calcium binding to TnC in solution and on the calcium sensitivity of myofilaments in skinned rabbit ventricular fibers in vitro. We measured [Ca2+]i and L-type calcium current (ICa) in ventricular myocytes from 3-wk-old and adult rabbits. The dissociation constant (Kd) of Ca-TncTnT1 in solution was smaller than that of Ca-TncTnT4 (mean ± SE: 0.52 ± 0.08 μmol/L versus 0.83 ± 0.09 μmol/L). The Ca2+ sensitivity of force development was greater in fibers reconstituted with rcTnT1 (pCa50 6.07 ± 0.04) than those reconstituted with rcTnT4 (pCa50 5.75 ± 0.07). Systolic [Ca]i was lower in 3-wk-old than adult cells (443 ± 35 nmol/L versus 882 ± 88 nmol/L) as was ICa (5.8 ± 0.9 pA/pF versus 14.2 ± 1.6 pA/pF). The higher calcium sensitivity of Tn-Ca binding and of force development conferred by rcTnT1 suggest that higher neonatal cTnT1 expression may partially compensate for the lower systolic [Ca2+]i.
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Details
- Title
- Development and cardiac contractility : Cardiac troponin T isoforms and cytosolic calcium in rabbit
- Creators
- Shannon J Mccall - Duke University HospitalRashid Nassar - Duke Medical CenterNadia N Malouf - University of North Carolina at Chapel HillAleister J Saunders - Drexel UniversityAnnette E Oakeley - Duke Medical CenterPaul M Henderson - Wakefield HospitalR. John Solaro - University of Illinois ChicagoGary J Pielak - University of North Carolina at Chapel HillKenneth A Alexander - University of ChicagoPage A. W Anderson - Duke Medical Center
- Publication Details
- Pediatric research, v 60(3), pp 276-281
- Publisher
- Lippincott Williams & Wilkins
- Number of pages
- 6
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Biology
- Web of Science ID
- WOS:000239861300007
- Scopus ID
- 2-s2.0-33747587851
- Other Identifier
- 991021448057004721
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Pediatrics