The effect of NADP+ on cardiomyocyte electrophysiological properties of C57BL/6 and mdx mice

Autor: G. I. Mamaeva, V. M. Mikhailov
Rok vydání: 2014
Předmět:
Zdroj: Cell and Tissue Biology. 8:160-165
ISSN: 1990-5203
1990-519X
DOI: 10.1134/s1990519x14020059
Popis: We have studied the influence of NADP+ on routine electrocardiography (ECG) in 6-month-old C57BL/6 and mdx mice. The animals were anesthetized by ether before ECG recording. ECG registration was carried out at a speed of 100 mm/s. The first ECG recording was made before intraperitoneal NADP+ injection in a dose of 13 or 80 mg/kg. The second ECG recording was made 10 min after NADP+ injection. Anesthesia was then terminated. The mice were occasionally anesthetized 45–60 min later, and the third ECG was recorded 1 h after injection of NADP+. ECG recording was carried out at a speed of 100 mm/s in standard leads I, II, and III and unipolar leads AvR, AvL, and AvF. Values of standard ECG characteristics, such as the P wave and the intervals PQ, QT, RR, and the QRS complex, were measured in milliseconds in standard lead II. We did not observe any differences between ECG magnitudes of 2- to 3-month-old C57BL/6 and mdx mice during trial experiments. Mice of both strains had a sinus rhythm in their heart rate. The QRS complex in mdx mice had a tendency to be larger than in C57BL/6 mice. Heart rates fluctuated between 722 ± 22 and 681 ± 21 beats per minute. The effect of NADP+ was studied in 6-month-old male mice. The increase in the RR interval and the decline in heart rate from 697 ± 21 to 461 ± 23 and 491 ± 28 beats per min for C57BL/6 mice (p < 0.01) and from 722 ± 28 beats per minute to 454 ± 31 beats per min for mdx mice were registered 10 min after NADP+ injection at a dose of 80 mg/kg. The increase in the RR interval can be explained by an increase in the QT interval. A statistically significant reduction in the QT interval leading to a diminished RR interval was observed in mdx mice 1 h after NADP+ injection. NADP+ at a dose of 13 mg/kg did not significantly change the ECG properties in mdx mice. ECG of mdx mice was characterized by negative repolarization of the T wave in 37% of all leads. The amount of leads with negative T-wave repolarization decreased up to 3% 1 h after NADP+ injection in dose of 80 mg/kg. The results have shown that cytomembranes of ventricular cardiac myocytes and the degree of oxidative stress are the main targets of the action of NADP+ in C57BL/6 and mdx mouse hearts.
Databáze: OpenAIRE
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