Related Experiment Videos
A5 noradrenergic unit activity and sympathetic nerve discharge in rats
D H Huangfu1, N Koshiya, P G Guyenet
1Department of Pharmacology, University of Virginia Health Sciences Center, Charlottesville 22908.
The American Journal of Physiology
|August 1, 1991
Summary
A5 noradrenergic neurons contribute to splanchnic sympathetic nerve discharge in rats. These neurons, identified by location and response to drugs, influence visceral vasomotor activity.
Area of Science:
- Neuroscience
- Physiology
Background:
- The role of A5 noradrenergic neurons in regulating sympathetic nerve activity is not fully understood.
- Splanchnic sympathetic nerve discharge (SSND) is crucial for controlling visceral blood flow.
Purpose of the Study:
- To investigate the contribution of A5 noradrenergic neurons to the generation of SSND in anesthetized rats.
Main Methods:
- Unit recording experiments were performed on halothane-anesthetized rats.
- A5 neurons were identified by location, antidromic activation from the thoracic spinal cord, and inhibition by clonidine.
- The effects of 6-hydroxydopamine and aortic depressor nerve stimulation were examined.
Main Results:
- Fifty-nine A5 neurons exhibited low firing rates and slow conduction velocities.
- Intraspinal 6-hydroxydopamine abolished antidromic activation in most tested A5 neurons.
- A5 neuron discharge correlated with SSND and preceded its peaks.
Conclusions:
- A significant portion of A5 neurons project to the intermediolateral cell column.
- A5 neurons are modulated by arterial pressure and aortic depressor nerve stimulation.
- Approximately 40% of A5 cells likely possess a visceral vasomotor sympathoexcitatory function.