Sympathetic activation during treadmill exercise in the conscious dog: assessment with spectral analysis of heart period and systolic pressure variabilities.
We studied in seven conscious dogs the dynamic rearrangements in neural control of heart rate and left ventricular pressure during treadmill exercise as assessed by spectral analysis. The presence, at rest, of a major high-frequency component (HF), an indicator of vagal tone, was reverted during exercise to a major low-frequency component (LF), an indicator of sympathetic activation. These changes were blunted by chronic beta and alpha 1 adrenergic receptor blockade.
Istituto Ricerche Cardiovascolari, Centro Ricerche Cardiovascolari C.N.R., Centro Fidia, Ospedale L. Sacco, Milano, Italy.
O
O
Rimoldi
M
M
Pagani
M R
MR
Pagani
G
G
Baselli
A
A
Malliani
D000818:Animals; D004285:Dogs; D004562:Electrocardiography; D006321:Heart / Q000294:innervation / Q000502:physiology*; D006339:Heart Rate; D005082:Physical Exertion; D013564:Sympathetic Nervous System / Q000502:physiology*; D013599:Systole