Rat caval vein myocardium undergoes changes in conduction characteristics during postnatal ontogenesis

Ivanova, A.D.; Samoilova, D.V.; Razumov, A.A.; Kuzmin, V.S.

Авторы: Ivanova Alexandra D., Samoilova Daria V., Razumov Artem A., Kuzmin Vlad S.
Журнал: Pflugers Archiv European Journal of Physiology
Том: 471
Номер: 11
Год издания: 2019
Издательство: Springer Verlag
Местоположение издательства: Germany
Первая страница: 1493
Последняя страница: 1503
DOI: 10.1007/s00424-019-02320-0
Аннотация: The electrophysiological properties of the superior vena cava (SVC) myocardium, which is considered a minor source of atrial arrhythmias, were studied in this study during postnatal development. Conduction properties were investigated in spontaneously active and electrically paced SVC preparations obtained from 7–60-day-old male Wistar rats using optical mapping and micro- electrode techniques. The presence ofhigh-conductance connexin 43 (Cx43) was evaluated in SVC cross-sections using immu- nofluorescence. It was found that SVC myocardium is excitable, electrically coupled with the atrial tissue, and conducts excitation waves at all stages ofpostnatal development. However, the conduction velocity (CV) ofexcitation and action potential (AP) upstroke velocity in SVCwere significantly lower in neonatal than in adult animals and increasedwith postnatal maturation. Connexins Cx43 were identified in both neonatal and adult rat SVC myocardium; however, the abundance of Cx43 was significantly less in neonates. The gap junction uncoupler octanol affected conduction more profound in the neonatal than in adult SVC. We demonstrated for the first time that the conduction characteristics of SVC myocardium change from a slow- conduction (nodal) to a high-conduction (working) phenotype during postnatal ontogenesis. An age-related CV increase may occur due to changes ofAP characteristics, electrical coupling, and Cx43 presence in SVC cardiomyocyte membranes. Observed changes may contribute to the low proarrhythmicity of adult caval vein cardiac tissue, while pre- or postnatal developmental abnormalities that delay the establishment of the working conduction phenotype may facilitate SVC proarrhythmia.
Добавил в систему: Иванова Александра Дмитриевна

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