| Autor: |
Kuzmina, E. S., Nechaeva, M. V., Avdonin, P. V. |
| Zdroj: |
Moscow University Biological Sciences Bulletin; 2024 Suppl 1, Vol. 79, pS59-S67, 9p |
| Abstrakt: |
The work was aimed at studying the role of the second messenger NAADP (Nicotinic Acid Adenine Dinucleotide Phosphate), which causes the release of Ca2+ ions from lysosomes and endosomes, in the regulation of heart contractions. Isolated hearts of the grape snail Helix pomatia and a chicken embryo were used as models. Using the membrane-permeable acetooxymethyl ester NAADP-AM, the authors showed that the nanomolar concentrations of NAADP increase the frequency and amplitude of spontaneous cardiac contractions in H. pomatia. The NAADP antagonist, NED19, dose-dependently reduces their frequency, completely blocking spontaneous contractions of the mollusk heart at a concentration of 5 μM without affecting the amplitude of contractions. The V-type H+-ATPase inhibitor bafilomycin A1 suppresses the accumulation of calcium ions in lysosomes and acidic endosomes. It has been shown that bafilomycin A1 causes attenuation of spontaneous contractions and cardiac arrest in H. pomatia. Serotonin increases the amplitude of contractions of the H. pomatia heart without affecting heart rate. NED19 at saturating concentrations (10 μM) reduces the frequency of contractions when the snail heart is activated by serotonin but only partially reduces their amplitude. The experiments with the isolated chick embryo heart showed that NED19 reduces the heart rate without affecting the amplitude of contractions. Based on the obtained data, a hypothesis was put forward that the release of calcium ions from lysosomes and endosomes under the influence of endogenous NAADP ensures the maintenance of spontaneous contractions of the heart. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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