Effects of vagotomy on cardiovascular and heart rate variability alterations following chronic normobaric hypoxia in adult rabbits

Biological research: BR

Esteban A. Moya¹  Matas Freire²  Rodrigo Del Rio³  Julio Alcayaga⁴  Rodrigo Iturriaga⁵ 

[1] Centro de Envejecimiento y Regeneracin (CARE-UC), Pontificia Universidad Catlica de Chile, Santiago, Chile;Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile;Laboratorio de Control Cardiorrespiratorio, Departamento de Fisiologa, Pontificia Universidad Catlica de Chile, Santiago, Chile;Laboratorio de Fisiologa Celular, Facultad de Ciencias, Universidad de Chile, Santiago, Chile;Laboratorio de Neurobiologa, Facultad de Ciencias Biolgicas, Pontificia Universidad Catlica de Chile, Santiago, Chile

关键词: Heart rate variability;    Chronic normobaric hypoxia;    Cardiovascular regulation;    Sympathetic control;    Vagal activity;    Poincaré plot;    Spectral components;   

DOI  :  10.1186/s40659-018-0207-2

学科分类：生物科学（综合）

来源: BioMed Central

【 摘 要 】

chronic hypoxia increases basal ventilation and pulmonary vascular resistance, with variable changes in arterial blood pressure and heart rate, but it’s impact on heart rate variability and autonomic regulation have been less well examined. We studied changes in arterial blood pressure, heart rate and heart rate variability (HRV) in rabbits subjected to chronic normobaric hypoxia (CNH; PB ~ 719 mmHg; FIO2 ~ 9.2%) for 14 days and assess the effect of autonomic control by acute bilateral vagal denervation. exposure to CNH stalled animal weight gain and increased the hematocrit, without affecting heart rate or arterial blood pressure. Nevertheless, Poincaré plots of the electrocardiographic R–R intervals showed a reduced distribution parallel to the line of identity, which interpreted as reduced long-term HRV. In the frequency domain, CNH reduced the very-low- (< 0.2 Hz) and high-frequency components (> 0.8 Hz) of the R–R spectrograms and produced a prominent component in the low-frequency component (0.2–0.5 Hz) of the power spectrum. In control and CNH exposed rabbits, bilateral vagotomy had no apparent effect on the short- and long-term HRV in the Poincaré plots. However, bilateral vagotomy differentially affected higher-frequency components (> 0.8 Hz); reducing it in control animals without modifying it in CNH-exposed rabbits. These results suggest that CNH exposure shifts the autonomic balance of heart rate towards a sympathetic predominance without modifying resting heart rate or arterial blood pressure.

【 授权许可】

CC BY