The snake heart pacemaker is localized near the sinoatrial valve

Denis V. Abramochkin*, Vladislav S. Kuzmin, Vladimir Matchkov, Andrey A. Kamensky, Tobias Wang

*Corresponding author af dette arbejde

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisLetterpeer review

2 Citationer (Scopus)
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Abstract

To provide the first description of the exact location of primary pacemaker of the squamate heart, we used sharp microelectrode impalements and optical mapping of isolated sinus venosus preparations from Burmese pythons. We located the dominant pacemaker site at the base of the right leaflet of the sinoatrial valve (SAV), but latent pacemakers were also identified in a circular region around the SAV. Acetylcholine (10-5 mol l-1) or noradrenaline (10-6 mol l-1) induced shifts of the leading pacemaker site to other points near the SAV. The ionic currents of most of the cardiomyocytes isolated enzymatically from the SAV region resembled those of typical working myocytes from the sinus venosus. However, seven cells lacked the background inward rectifier current (IK1) and had a timedependent hyperpolarization-induced inward current identified as the 'funny' pacemaker current (If ). Therefore, the region proximal to SAV demonstrates pacemaking activity and contains cells that resemble the electrophysiological properties of mammalian pacemaker myocytes.

OriginalsprogEngelsk
Artikelnummerjeb242778
TidsskriftJournal of Experimental Biology
Vol/bind224
Nummer16
Antal sider7
ISSN0022-0949
DOI
StatusUdgivet - aug. 2021

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