ОСОБЕННОСТИ АНАТОМИИ И ФИЗИОЛОГИИ СЕРДЦА БЕСЧЕЛЮСТНЫХ РЫБООБРАЗНЫХ И ЧЕЛЮСТНЫХ РЫБ
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Ключевые слова

циклостомы
рыбы
сердце
гипоксия
проводящая система сердца
HCN-каналы

Аннотация

Сердце бесчелюстных рыбообразных (Cyclostomata; миноги, миксины) и костистых рыб (Teleostei) гомологично сердцу высших позвоночных животных. Изучение сердца архаичных Cyclostomata и Teleostei, обладающих разным эволюционным «возрастом», молекулярно-генетическими характеристиками и переносимостью гипоксии, представляет особый интерес при поиске факторов устойчивости миокарда к кислородной недостаточности. Cyclostomata и Teleostei объединяет жаберный тип дыхания и наличие только одного круга кровообращения. Главный сократительный орган, обеспечивающий циркуляцию крови — жаберное сердце — состоит из двух камер. Миксины составляют самый старый класс существующих позвоночных, кровообращение которых поддерживается за счет не имеющего иннервации (аневрального) жаберного сердца и трех наборов добавочных «сердец». Миноги являются первыми позвоночными, у которых появляется иннервация сердца в виде блуждающего нерва. В свою очередь, Teleostei впервые получают симпатическую иннервацию сердца, которая осуществляется «вагосимпатическими стволами». В сердце Cyclostomata и Teleostei не найдено признаков организации проводящей системы, подобной таковой у высших позвоночных, что не отменяет существования четко скоординированного механизма распространения возбуждения и сокращения миокарда. Механизм генерации сердечного ритма связывает возникающие и распространяющиеся в миокарде электрические процессы с экспрессией управляемых циклическими нуклеотидами гиперполяризационно-активируемых каналов (HCN-каналов). В сердце миксин и костистых рыб экспрессируется шесть изоформ HCN-каналов. Регулируемая плотность распределения HCN-каналов в миокарде может предшествовать проводящей системе сердца, характерной для высших позвоночных. Экспрессия HCN2, HCN3 и HCN4 в сердце миксин, как реликтового таксона, предполагает их присутствие в миокарде общего предка позвоночных до момента дивергенции с Myxiniformes, что допускает особую значимость HCN2-HCN4 в формировании сердечной активности в момент возникновения камерного миогенного сердца. Предполагается, что эволюционный прогресс архаичных групп «первых» позвоночных направлен на «создание» более быстрой эффекторной системы регуляции сердечной деятельности и двойного (возбуждающего/тормозного) контроля функций миокарда.

https://doi.org/10.31857/S0044452921020029
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