Effects of vagotomy on cardiovascular and heart rate variability alterations following chronic normobaric hypoxia in adult rabbits
Abstract Background 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 pr...
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| Format: | Article |
| Language: | English |
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BMC
2018-12-01
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| Series: | Biological Research |
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| Online Access: | http://link.springer.com/article/10.1186/s40659-018-0207-2 |
| _version_ | 1819163830543974400 |
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| author | Julio Alcayaga Rodrigo Del Rio Esteban A. Moya Matías Freire Rodrigo Iturriaga |
| author_facet | Julio Alcayaga Rodrigo Del Rio Esteban A. Moya Matías Freire Rodrigo Iturriaga |
| author_sort | Julio Alcayaga |
| collection | DOAJ |
| description | Abstract Background 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. Results 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. Conclusions 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. |
| first_indexed | 2024-12-22T17:50:22Z |
| format | Article |
| id | doaj.art-51fd4738e04b4106bf7b1273ebded6a0 |
| institution | Directory Open Access Journal |
| issn | 0717-6287 |
| language | English |
| last_indexed | 2024-12-22T17:50:22Z |
| publishDate | 2018-12-01 |
| publisher | BMC |
| record_format | Article |
| series | Biological Research |
| spelling | doaj.art-51fd4738e04b4106bf7b1273ebded6a02022-12-21T18:18:11ZengBMCBiological Research0717-62872018-12-0151111410.1186/s40659-018-0207-2Effects of vagotomy on cardiovascular and heart rate variability alterations following chronic normobaric hypoxia in adult rabbitsJulio Alcayaga0Rodrigo Del Rio1Esteban A. Moya2Matías Freire3Rodrigo Iturriaga4Laboratorio de Fisiología Celular, Facultad de Ciencias, Universidad de ChileLaboratorio de Control Cardiorrespiratorio, Departamento de Fisiología, Pontificia Universidad Católica de ChileLaboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de ChileLaboratorio de Fisiología Celular, Facultad de Ciencias, Universidad de ChileLaboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de ChileAbstract Background 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. Results 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. Conclusions 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.http://link.springer.com/article/10.1186/s40659-018-0207-2Heart rate variabilityChronic normobaric hypoxiaCardiovascular regulationSympathetic controlVagal activityPoincaré plot |
| spellingShingle | Julio Alcayaga Rodrigo Del Rio Esteban A. Moya Matías Freire Rodrigo Iturriaga Effects of vagotomy on cardiovascular and heart rate variability alterations following chronic normobaric hypoxia in adult rabbits Biological Research Heart rate variability Chronic normobaric hypoxia Cardiovascular regulation Sympathetic control Vagal activity Poincaré plot |
| title | Effects of vagotomy on cardiovascular and heart rate variability alterations following chronic normobaric hypoxia in adult rabbits |
| title_full | Effects of vagotomy on cardiovascular and heart rate variability alterations following chronic normobaric hypoxia in adult rabbits |
| title_fullStr | Effects of vagotomy on cardiovascular and heart rate variability alterations following chronic normobaric hypoxia in adult rabbits |
| title_full_unstemmed | Effects of vagotomy on cardiovascular and heart rate variability alterations following chronic normobaric hypoxia in adult rabbits |
| title_short | Effects of vagotomy on cardiovascular and heart rate variability alterations following chronic normobaric hypoxia in adult rabbits |
| title_sort | effects of vagotomy on cardiovascular and heart rate variability alterations following chronic normobaric hypoxia in adult rabbits |
| topic | Heart rate variability Chronic normobaric hypoxia Cardiovascular regulation Sympathetic control Vagal activity Poincaré plot |
| url | http://link.springer.com/article/10.1186/s40659-018-0207-2 |
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