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Sympathetic burst activity: characteristics and significance
1Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Victoria, Australia. r.mcallen@howard_florey.unimelb.edu.au
Clinical and Experimental Pharmacology & Physiology
|November 18, 1997
Summary
Sympathetic nerve activity in mammals and humans occurs in synchronized bursts, not regular firing. This bursting phenomenon, driven by neuronal populations, influences physiological control despite slow neuroeffector responses.
Area of Science:
- Neuroscience
- Physiology
Background:
- Mammalian sympathetic nerve activity is characterized by synchronized bursts of neuronal firing.
- This bursting pattern is observed across various sympathetic pathways, including vasomotor, cardiac, and sudomotor fibers.
Purpose of the Study:
- To investigate the characteristics and underlying mechanisms of sympathetic nerve bursting.
- To explore the control of burst properties and their physiological implications.
Main Methods:
- Analysis of sympathetic nerve activity recordings.
- Examination of neuronal firing patterns and population dynamics.
Main Results:
- Sympathetic activity is intrinsically bursty but not regular, a population phenomenon.
- Burst amplitude and probability are independently controlled, with baroreceptors primarily influencing probability.
- Burst generation is influenced by preganglionic neuron properties and occurs downstream of the rostral ventrolateral medulla.
Conclusions:
- Sympathetic bursting is a fundamental aspect of neural control, enhancing the dynamic range of responses.
- Understanding burst generation mechanisms is crucial for comprehending sympathetic regulation.