Dynamics of muscle microcirculatory oxygen exchange.
OBJECTIVE
Beyond the initial cardiodynamic "Phase I," pulmonary oxygen uptake (VO(2)) kinetics are dictated largely by, and resemble closely, the VO(2) of the exercising muscles (VO(2)m). Within those muscles, the microcirculation is responsible for affecting almost all blood-myocyte O(2) transfer, and thus, observations at this site may provide key insights into muscle oxidative function in health and dysfunction in disease.


METHODS
Recently, a novel combination of microscopy and phosphorescence quenching techniques has been utilized to understand the dynamics of microvascular O(2) delivery (VO(2)m) and muscle O(2) utilization (VO(2)m) at the onset of muscle contractions.


RESULTS
These experiments have addressed longstanding questions regarding the site of control of VO(2)m kinetics and provide a first look at capillary hemodynamics at exercise onset in healthy muscle and their derangements resulting from chronic diseases such as heart failure and diabetes.


CONCLUSIONS
This paper will review these novel findings within our current understanding of microcirculatory control and blood-myocyte O(2) transfer.
Poole
David C
DC
Department of Kinesiology, Kansas State University, Manhattan, USA. poole@vet.ksu.edu
Behnke
Brad J
BJ
Padilla
Danielle J
DJ
D002318:Cardiovascular Diseases / Q000378:metabolism / Q000503:physiopathology; D004912:Erythrocytes / Q000378:metabolism; D015444:Exercise / Q000502:physiology; D006801:Humans; D007700:Kinetics; D008833:Microcirculation / Q000378:metabolism; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D010313:Partial Pressure
D010100:Oxygen