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Feed-forward changes in carotid blood flow velocity during active standing
Kazuyoshi Kitaoka1, Hajime Miura, Mitsuo Kitamura
1Department of Physiology, The University of Tokushima Graduate School, Tokushima 770-8503, Japan. kitaoka@basic.med.tokushima-u.ac.jp
Neuroscience Letters
|October 26, 2010
Summary
Anticipatory cardiovascular regulation may occur before standing, indicated by changes in blood flow velocity and cerebral blood volume. This feed-forward mechanism, possibly triggered by central command, helps maintain brain blood flow during the transition to upright posture.
Area of Science:
- Physiology
- Cardiovascular Regulation
- Neuroscience
Background:
- Orthostatic changes transiently disrupt circulatory control.
- Cardiovascular feedback systems activate to counteract instability during postural changes.
Purpose of the Study:
- To investigate anticipatory cardiovascular regulation preceding active standing.
- To determine if central command influences cardiovascular adjustments before postural transition.
Main Methods:
- Continuous recording of common carotid artery blood flow velocity (BFV).
- Measurement of cerebral blood volume (CBV) using oxyhemoglobin levels.
- Comparison of BFV and CBV responses during reaction-time versus self-paced standing in healthy men.
Main Results:
- A significant decrease in maximum BFV occurred before standing in the reaction-time condition, correlating with systolic blood pressure changes.
- Anticipatory BFV decrease was absent during self-paced standing, with subsequent declines in BFV parameters.
- Cerebral blood volume showed a significant increase in oxyhemoglobin before standing in the reaction-time condition.
Conclusions:
- Evidence suggests a feed-forward cardiovascular regulatory mechanism activated by central command before standing.
- This anticipatory regulation may play a role in maintaining cerebral perfusion during the transition to an upright posture.
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