Related Experiment Videos
Central command increases sympathetic nerve activity during spontaneous locomotion in cats
G Hajduczok1, J S Hade, A L Mark
1Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242.
Circulation Research
|July 1, 1991
Summary
Central command directly increases sympathetic nerve activity (SNA) in cats during locomotion, even without sensory feedback. This finding clarifies the neural control of exercise responses.
Area of Science:
- Exercise Physiology
- Neuroscience
- Autonomic Nervous System Regulation
Background:
- The role of central command versus afferent input in regulating sympathetic nerve activity (SNA) during exercise is debated.
- Previous studies in humans suggest central command influences sudomotor activity but not vasoconstrictor outflow to skin and muscle.
Purpose of the Study:
- To investigate the influence of central command on renal and lumbar sympathetic nerve activity (SNA) during spontaneous locomotion in decorticate cats.
Main Methods:
- Studied unanesthetized decorticate cats exhibiting spontaneous or electrically stimulated locomotion.
- Recorded mean arterial pressure (MAP) and SNA in the presence and absence of skeletal muscle and baroreceptor afferent input.
- Baroreceptor denervation was performed in some animals.
Main Results:
- Spontaneous locomotion increased MAP and renal SNA significantly.
- In paralyzed cats, fictive locomotion elevated MAP, renal SNA, and lumbar SNA.
- Electrical stimulation of the locomotor region also increased MAP and renal SNA.
- Baroreceptor denervation did not alter these increases.
Conclusions:
- Central command can independently increase sympathetic neural drive to the kidneys and lumbar regions in decorticate cats.
- This sympathetic activation during locomotion occurs without input from contracting muscles or baroreceptors.