Mouchtouri Eleni-Taxiarchia, Konstantinou Thomas, Lekkas Panagiotis, Lianopoulou Alexandra, Kotsaridou Zoi, Mourouzis Iordanis, Pantos Constantinos, Kolettis Theofilos M
Department of Cardiology, Medical School, University of Ioannina, 45500 Ioannina, Greece.
Cardiovascular Research Institute, 45500 Ioannina, Greece.
Biology (Basel). 2023 Nov 5;12(11):1401. doi: 10.3390/biology12111401.
The ubiquitous peptide endothelin is currently under investigation as a modulatory factor of autonomic responses to acute emotional stress. Baseline plasma levels of endothelin alter blood pressure responses, but it remains unclear whether autonomic activity and arrhythmogenesis (i.e., brady- or tachyarrhythmias) are affected. We recorded sympathetic and vagal indices (derived from heart rate variability analysis), rhythm disturbances, voluntary motion, and systolic blood pressure after acute emotional stress in conscious rats with implanted telemetry devices. Two strains were compared, namely wild-type and ET-deficient rats, the latter displaying elevated plasma endothelin. No differences in heart rate or blood pressure were evident, but sympathetic responses were blunted in ET-deficient rats, contrasting prompt activation in wild-type rats. Vagal withdrawal was observed in both strains at the onset of stress, but vagal activity was subsequently restored in ET-deficient rats, accompanied by low voluntary motion during recovery. Reflecting such distinct autonomic patterns, frequent premature ventricular contractions were recorded in wild-type rats, as opposed to sinus pauses in ET-deficient rats. Thus, chronically elevated plasma endothelin levels blunt autonomic responses to acute emotional stress, resulting in vagal dominance and bradyarrhythmias. Our study provides further insights into the pathophysiology of stress-induced tachyarrhythmias and syncope.
普遍存在的肽类内皮素目前正作为对急性情绪应激自主反应的调节因子进行研究。内皮素的基础血浆水平会改变血压反应，但自主神经活动和心律失常（即缓慢性或快速性心律失常）是否受到影响仍不清楚。我们在植入遥测装置的清醒大鼠急性情绪应激后记录了交感神经和迷走神经指标（源自心率变异性分析）、节律紊乱、自主运动和收缩压。比较了两种品系，即野生型和内皮素缺陷型大鼠，后者血浆内皮素水平升高。心率或血压无明显差异，但内皮素缺陷型大鼠的交感神经反应减弱，与野生型大鼠的迅速激活形成对比。在应激开始时，两种品系均观察到迷走神经撤离，但内皮素缺陷型大鼠随后迷走神经活动恢复，恢复期间自主运动较少。反映出这种不同的自主神经模式，野生型大鼠记录到频繁的室性早搏，而内皮素缺陷型大鼠则出现窦性停搏。因此，长期升高的血浆内皮素水平会减弱对急性情绪应激的自主神经反应，导致迷走神经占优势和缓慢性心律失常。我们的研究为应激诱导的快速性心律失常和晕厥的病理生理学提供了进一步的见解。
