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Cat diencephalic neurons with sympathetic nerve-related activity
K J Varner1, S M Barman, G L Gebber
1Department of Pharmacology and Toxicology, Michigan State University, East Lansing 48824.
The American Journal of Physiology
|February 1, 1988
Summary
Hypothalamic and medial thalamic neurons contribute to sympathetic nerve discharge (SND) in cats. These neurons influence both rhythmic and irregular components of SND, impacting cardiac function.
Area of Science:
- Neuroscience
- Cardiovascular Physiology
Background:
- Previous research indicated hypothalamic or medial thalamic lesions affect sympathetic nerve discharge (SND).
- This suggested these diencephalic regions might house neurons integral to SND control.
Purpose of the Study:
- To investigate the role of hypothalamic and medial thalamic neurons in generating sympathetic nerve discharge (SND).
- To determine if these neurons contribute to the rhythmic and aperiodic components of SND.
Main Methods:
- Anesthetized cats were used for electrophysiological recordings.
- Spike-triggered averaging was employed to analyze neuronal activity relative to SND.
- Microstimulation was performed at recording sites to assess effects on SND.
Main Results:
- Two types of neurons in the hypothalamus and medial thalamus exhibited sympathetic nerve-related activity.
- Type 1 neurons synchronized with aperiodic SND events; Type 2 neurons synchronized with rhythmic SND (2-6 Hz).
- Some Type 2 neurons showed cardiac-related activity, and microstimulation increased SND.
Conclusions:
- Hypothalamic and medial thalamic neurons are implicated in generating both rhythmic and aperiodic components of sympathetic nerve discharge (SND).
- These findings support the contribution of diencephalic neurons to cardiovascular regulation via SND.