TY - JOUR
T1 - Catecholamines are key modulators of ventricular repolarization patterns in the ball python (Python regius)
AU - Boukens, Bastiaan J. D.
AU - Joyce, William
AU - Kristensen, Ditte Lind
AU - Hooijkaas, Ingeborg
AU - Jongejan, Aldo
AU - Wang, Tobias
AU - Jensen, Bjarke
N1 - Funding Information: B.J.D. Boukens was supported by the Dutch Heart Foundation (2016T047). W. Joyce is supported by a Novo Nordisk Foundation grant (NNF19OC0055842), and T. Wang was supported by the Danish Council for Independent Research/Natural Sciences. The authors declare no competing financial interests. Publisher Copyright: © 2021 Boukens et al.
PY - 2022/2/7
Y1 - 2022/2/7
N2 - Ectothermic vertebrates experience daily changes in body temperature, and anecdotal observations suggest these changes affect ventricular repolarization such that the T-wave in the ECG changes polarity. Mammals, in contrast, can maintain stable body temperatures, and their ventricular repolarization is strongly modulated by changes in heart rate and by sympathetic nervous system activity. The aim of this study was to assess the role of body temperature, heart rate, and circulating catecholamines on local repolarization gradients in the ectothermic ball python (Python regius). We recorded body-surface electrocardiograms and performed open-chest high-resolution epicardial mapping while increasing body temperature in five pythons, in all of which there was a change in T-wave polarity. However, the vector of repolarization differed between individuals, and only a subset of leads revealed T-wave polarity change. RNA sequencing revealed regional differences related to adrenergic signaling. In one denervated and Ringer's solution-perfused heart, heating and elevated heart rates did not induce change in T-wave polarity, whereas noradrenaline did. Accordingly, electrocardiograms in eight awake pythons receiving intra-arterial infusion of the β-adrenergic receptor agonists adrenaline and isoproterenol revealed T-wave inversion in most individuals. Conversely, blocking the β-adrenergic receptors using propranolol prevented T-wave change during heating. Our findings indicate that changes in ventricular repolarization in ball pythons are caused by increased tone of the sympathetic nervous system, not by changes in temperature. Therefore, ventricular repolarization in both pythons and mammals is modulated by evolutionary conserved mechanisms involving catecholaminergic stimulation.
AB - Ectothermic vertebrates experience daily changes in body temperature, and anecdotal observations suggest these changes affect ventricular repolarization such that the T-wave in the ECG changes polarity. Mammals, in contrast, can maintain stable body temperatures, and their ventricular repolarization is strongly modulated by changes in heart rate and by sympathetic nervous system activity. The aim of this study was to assess the role of body temperature, heart rate, and circulating catecholamines on local repolarization gradients in the ectothermic ball python (Python regius). We recorded body-surface electrocardiograms and performed open-chest high-resolution epicardial mapping while increasing body temperature in five pythons, in all of which there was a change in T-wave polarity. However, the vector of repolarization differed between individuals, and only a subset of leads revealed T-wave polarity change. RNA sequencing revealed regional differences related to adrenergic signaling. In one denervated and Ringer's solution-perfused heart, heating and elevated heart rates did not induce change in T-wave polarity, whereas noradrenaline did. Accordingly, electrocardiograms in eight awake pythons receiving intra-arterial infusion of the β-adrenergic receptor agonists adrenaline and isoproterenol revealed T-wave inversion in most individuals. Conversely, blocking the β-adrenergic receptors using propranolol prevented T-wave change during heating. Our findings indicate that changes in ventricular repolarization in ball pythons are caused by increased tone of the sympathetic nervous system, not by changes in temperature. Therefore, ventricular repolarization in both pythons and mammals is modulated by evolutionary conserved mechanisms involving catecholaminergic stimulation.
UR - http://www.scopus.com/inward/record.url?scp=85123972889&partnerID=8YFLogxK
U2 - https://doi.org/10.1085/jgp.202012761
DO - https://doi.org/10.1085/jgp.202012761
M3 - Article
C2 - 34910097
SN - 0022-1295
VL - 154
JO - Journal of general physiology
JF - Journal of general physiology
IS - 2
M1 - e202012761
ER -