Effects of Sustained Length-Dependent Activation on In Situ Cross-Bridge Dynamics in Rat Hearts

James Todd Pearson, Mikiyasu Shirai, Hirotsugu Tsuchimochi, Daryl O Schwenke, Takayuki Ishida, Kenji Kangawa, Hiroyuki Suga, Naoto Yagi

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Abstract

The cellular basis of the length-dependent increases in contractile force in the beating heart has remained unclear. Our aim was to investigate whether length-dependent mediated increases in contractile force are correlated with myosin head proximity to actin filaments, and presumably the number of cross-bridges activated during a contraction. We therefore employed x-ray diffraction analyses of beat-to-beat contractions in spontaneously beating rat hearts under open-chest conditions simultaneous with recordings of left ventricle (LV) pressure-volume. Regional x-ray diffraction patterns were recorded from the anterior LV free wall under steady-state contractions and during acute volume loading (intravenous lactate Ringers infusion at 60 ml/h,
Original languageEnglish
Pages (from-to)4319 - 4329
Number of pages11
JournalBiophysical Journal
Volume93
Issue number12
DOIs
Publication statusPublished - 2007

Cite this

Pearson, J. T., Shirai, M., Tsuchimochi, H., Schwenke, D. O., Ishida, T., Kangawa, K., Suga, H., & Yagi, N. (2007). Effects of Sustained Length-Dependent Activation on In Situ Cross-Bridge Dynamics in Rat Hearts. Biophysical Journal, 93(12), 4319 - 4329. https://doi.org/10.1529/biophysj.107.111740