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Life Sci. 2014 Nov 24;118(2):281-7. doi: 10.1016/j.lfs.2014.01.069. Epub 2014 Feb 3.

Endothelin B-receptors and sympathetic activation: impact on ventricular arrhythmogenesis during acute myocardial infarction.

Author information

1
Department of Cardiology, University of Ioannina, Ioannina, Greece; Cardiovascular Research Institute, Ioannina and Athens, Greece. Electronic address: thkolet@cc.uoi.gr.
2
Department of Cardiology, University of Ioannina, Ioannina, Greece.
3
Department of Cardiology, University of Ioannina, Ioannina, Greece; Cardiovascular Research Institute, Ioannina and Athens, Greece; Experimental Research Center ELPEN, Pikermi, Athens, Greece.
4
Department of Materials Science and Engineering, University of Ioannina, Greece.
5
Department of Cardiology, University of Ioannina, Ioannina, Greece; Cardiovascular Research Institute, Ioannina and Athens, Greece.
6
Engineering Informatics and Telecommunications, University of Western Macedonia, Kozani, Greece.
7
Cardiovascular Research Institute, Ioannina and Athens, Greece; Experimental Research Center ELPEN, Pikermi, Athens, Greece.
8
Cardiovascular Research Institute, Ioannina and Athens, Greece; First Department of Cardiology, Red Cross Hospital, Athens, Greece.

Abstract

AIMS:

We investigated the role of endothelin-B receptors on sympathetic activation originating from the adrenal gland or from the myocardium and its impact on arrhythmogenesis during acute myocardial infarction.

MAIN METHODS:

We studied two groups of rats (n=120, 284±2 g), namely wild-type and ETB-deficient. Myocardial infarction was induced by permanent ligation of the left coronary artery and ventricular tachyarrhythmias were evaluated from continuous electrocardiographic recordings. Sympathetic activation, measured by indices of heart rate variability, was evaluated after adrenalectomy or catecholamine depletion induced by reserpine. Acute left ventricular failure was assessed by total animal activity.

KEY FINDINGS:

Adrenalectomy decreased the total duration of tachyarrhythmias in ETB-deficient rats, but their incidence remained higher, compared to wild-type rats. After reserpine, heart rate variability indices and tachyarrhythmias were similar in the two groups during the initial, ischaemic phase. During evolving infarction, tachyarrhythmia duration was longer in ETB-deficient rats, despite lower sympathetic activation. Heart rate was lower in ETB-deficient rats throughout the 24-hour observation period, whereas activity was comparable in the two groups.

SIGNIFICANCE:

Endothelin-B receptors modulate sympathetic activation during acute myocardial infarction not only in the ventricular myocardium, but also in the adrenal gland. Sympathetic activation markedly increases early-phase ventricular tachyarrhythmias, but other mechanisms involving the endothelin system underlie delayed arrhythmogenesis.

KEYWORDS:

Adrenal gland; Endothelin-B receptor; Myocardial infarction; Ventricular tachyarrhythmias

PMID:
24503339
DOI:
10.1016/j.lfs.2014.01.069
[Indexed for MEDLINE]
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