Journal Article

PUBDB-2026-00948

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Effects of cooling on pig heart excitation and contraction

Li, M.Extern* ; Persson, L. B. (Corresponding author)Extern* ; Schwartzkopf, M.DESY* ; Steen, E. ; Terry, A.Extern* ; Wohlfart, B.Extern* ; Steen, S. (Corresponding author) ; Arner, A. (Corresponding author)Extern*

2026
Frontiers Media Lausanne

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Please use a persistent id in citations: doi:10.3389/fcvm.2026.1753083  doi:10.3204/PUBDB-2026-00948

Abstract: Although variations in temperature have a profound impact on cardiac function, little is known regarding the excitation and contractile parameters over a broad temperature interval. In view of the clinical applications of lowered temperature in resuscitation and in cardiac preservation/evaluation for transplantation, we have examined the contractile function using Langendorff perfused hearts and isolated trabecular muscle from pig, in combination with electrophysiology and X-ray diffraction. Lowered temperature in the range 37 to 22oC was associated with an increase in systolic pressure and active force. In permeabilized preparations, force and Ca2+ sensitivity decreased with temperature, showing that the increased force down to 22oC in the intact heart and trabeculae was not due to changes in thin filament regulation, but most likely to increased activator [Ca2+]. At lower temperature (<22oC), force in the heart decreased, suggesting that the temperature effects in the regulatory system became dominating. ECG analysis showed that frequency was lowered and that PQ-, QS- and QT- times were prolonged at lower temperature. This was associated with a gradual depolarization of the cell membrane, prolonged action potential and an attenuation of the fast upstroke phase. These changes in rise time and amplitude of the action potential would predispose for uneven propagation and arrhythmia as temperature is lowered. At the same time, the prolonged action potential can be associated with an increased [Ca2+] at lower temperature. Small angle X-ray diffraction showed that the filament lattice of intact trabecular muscle tended to swell at low temperature (10 vs 22oC) and revealed a mass transfer from myosin to actin filaments, which would reflect changes in cellular physiology and contractile system structure at low temperature

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Contributing Institute(s):

1. FS DOOR-User (FS DOOR-User)
2. Experimentebetreuung PETRA III (FS-PET-D)

Research Program(s):

1. 633 - Life Sciences – Building Blocks of Life: Structure and Function (POF4-633) (POF4-633)
2. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
3. SWEDEN-DESY - SWEDEN-DESY Collaboration (2020_Join2-SWEDEN-DESY) (2020_Join2-SWEDEN-DESY)

Experiment(s):

1. PETRA Beamline P03 (PETRA III)

Appears in the scientific report 2026

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Database coverage:
; ; ; ; Article Processing Charges ; Clarivate Analytics Master Journal List ; Current Contents - Clinical Medicine ; DOAJ Seal ; Essential Science Indicators ; Fees ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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