Preferential Expression of Ca2+-Stimulable Adenylyl Cyclase III in the Supraventricular Area, including Arrhythmogenic Pulmonary Vein of the Rat Heart

Autor: Yosuke Okamoto, Naing Ye Aung, Masahiro Tanaka, Yuji Takeda, Daichi Takagi, Wataru Igarashi, Kuniaki Ishii, Mitsunori Yamakawa, Kyoichi Ono
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Biomolecules, Vol 12, Iss 5, p 724 (2022)
Druh dokumentu: article
ISSN: 2218-273X
DOI: 10.3390/biom12050724
Popis: Ectopic excitability in pulmonary veins (PVs) is the major cause of atrial fibrillation. We previously reported that the inositol trisphosphate receptor in rat PV cardiomyocytes cooperates with the Na+-Ca2+ exchanger to provoke ectopic automaticity in response to norepinephrine. Here, we focused on adenylyl cyclase (AC) as another effector of norepinephrine stimulation. RT-PCR, immunohistochemistry, and Western blotting revealed that the abundant expression of Ca2+-stimulable AC3 was restricted to the supraventricular area, including the PVs. All the other AC isotypes hardly displayed any region-specific expressions. Immunostaining of isolated cardiomyocytes showed an enriched expression of AC3 along the t-tubules in PV myocytes. The cAMP-dependent response of L-type Ca2+ currents in the PV and LA cells is strengthened by the 0.1 mM intracellular Ca2+ condition, unlike in the ventricular cells. The norepinephrine-induced automaticity of PV cardiomyocytes was reversibly suppressed by 100 µM SQ22536, an adenine-like AC inhibitor. These findings suggest that the specific expression of AC3 along t-tubules may contribute to arrhythmogenic automaticity in rat PV cardiomyocytes.
Databáze: Directory of Open Access Journals
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