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Temperature Effects on the Chick Embryonic Heart Function
Author(s) -
Vostarek Frantisek,
Svatunkova Jarmila,
Sedmera David
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.1042.5
Subject(s) - in ovo , ventricle , medicine , chemistry , stimulation , biophysics , anatomy , cardiology , biology , embryo , microbiology and biotechnology
The function of the embryonic heart is strongly affected by temperature. Changes in the kinetics of ion channels are crucial for generation and propagation of electricity. We set to analyze in detail the effects of temperature changes on electrical activity of the embryonic chick heart using in vitro high‐speed calcium imaging and in ovo video microscopy. In embryonic day 4 hearts we found that a decrease in temperature from 37 °C to 34 °C lead in vitro to a 22 % drop of the intrinsic heart rate and unchanged amplitude of Ca2+ transients, compared to a 25% deceleration between 37 °C and 34 °C in ovo. Increase in temperature from 37 °C to 40 °C lead in vivo to 23% and in ovo to 20 % acceleration of the intrinsic heart rate, and a significant decrease in amplitude of Ca2+ transients (atrium ‐35%, ventricle ‐38%). Hyperthermia in vitro increased the incidence of complete atrioventricular (AV) blocks, while no complete AV block was observed in hypothermia. Similar situation was recorded in ovo . Electrical stimulation experiments in ovo suggested that the AV blocks were caused by hypoxia a not by the tachycardia per se . Activation maps placed the location of the AV block at the inner curvature and the AV canal‐ventricular boundary along the outer curvature. Temperature is thus an important epigenetic factor influencing the function of the developing cardiac conduction system. Increased temperature augments the metabolic requirements of the myocardium, resulting in a relative hypoxia and AV conduction disturbances. Supported by GACR P302/11/1308 (DS) and GAUK 716214 (FV).