| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Toxicology, Lovelace Respiratory Research Institute, Albuquerque, NM, USA
2 Department of Anesthesiology, Chiba University School of Medicine, Chiba, Japan
3 Department of Medical Physics, Brody School of Medicine, East Carolina University, Greenville, NC, USA
4 Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
5 Department of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
* To whom correspondence should be addressed. E-mail: mcampen{at}lrri.org.
Heart rate variability (HRV) is a well characterized, noninvasive means of assessing cardiac autonomic nervous system activity. This study examines the basic cardiac responses to hypoxic and hypercapnic challenges in seven strains of commonly used inbred mice (A/J, Balb/cJ, C3H/HeJ, C57BL/6J, CBA/J, DBA/2J, and FVB/J). Adult male mice, 8 - 12 weeks of age were chronically instrumented a femoral artery catheter for the continuous measurement of systemic arterial blood pressure (PSA) and heart rate (HR). Mice were exposed to multiple 4-minute periods of hypoxia (10% O2), hypercapnia (5% CO2), and combined hypoxia/hypercapnia (10% O2 + 5% CO2). HRV was derived from pulse intervals of the blood pressure tracings. Hypoxia induced increases in high frequency (HF) HRV power and decreased low frequency (LF) HRV power in most strains. Hypercapnia led to decreased HF HRV power and increased LF HRV power in most strains. Strain differences were most notable in regards to the concomitant exposures of hypoxia and hypercapnia, with FVB/J mice mirroring their own response to hypercapnia alone, while CBA/J mice mirrored their own responses to hypoxia. As blood pressure is most likely the driving factor for heart rate changes via the baroreflex pathway, it is interesting that LF, considered to reflect cardiac sympathetic activity, was negatively correlated with heart rate, suggesting that LF changes are driven by baroreflex oscillation and not necessarily by absolute sympathetic or parasympathetic activity to the heart. These findings suggest that genetic background can influence the centrally mediated cardiovascular responses to basic hypoxic and hypercapnic challenges.
This article has been cited by other articles:
|
|
 |
|
  J. Thireau, B. L. Zhang, D. Poisson, and D. Babuty Heart rate variability in mice: a theoretical and practical guide Exp Physiol, January 1, 2008; 93(1): 83 - 94. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. F. Zwemer, M. Y. Song, K. A. Carello, and L. G. D'Alecy Strain differences in response to acute hypoxia: CD-1 versus C57BL/6J mice J Appl Physiol, January 1, 2007; 102(1): 286 - 293. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. P.A. Mammen, J. M. Shelton, Q. Ye, S. B. Kanatous, A. J. McGrath, J. A. Richardson, and D. J. Garry Cytoglobin Is a Stress-responsive Hemoprotein Expressed in the Developing and Adult Brain J. Histochem. Cytochem., December 1, 2006; 54(12): 1349 - 1361. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
