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Sympathetic denervation blocks blood pressure elevation in episodic hypoxia
E C Fletcher1, J Lesske, J Culman
1Institute for High Blood Pressure Research, Ruprecht-Karls University, Heidelberg, Germany.
Hypertension (Dallas, Tex. : 1979)
|November 1, 1992
Summary
Repetitive episodic hypoxia causes chronic high blood pressure in rats. Peripheral sympathetic nervous system denervation blocked this effect, indicating its necessity for hypoxia-induced hypertension.
Area of Science:
- Cardiovascular Physiology
- Neuroscience
- Respiratory Physiology
Background:
- Repetitive episodic hypoxia can lead to chronic increases in arterial blood pressure.
- The role of the peripheral sympathetic nervous system in this response is not fully understood.
Purpose of the Study:
- To investigate whether denervation of the peripheral sympathetic nervous system prevents the persistent elevation of arterial blood pressure induced by episodic hypoxia.
Main Methods:
- A rat model was used with chemical sympathetic denervation via 6-hydroxydopamine injections.
- Experimental groups included denervated hypoxia-exposed, denervated control, vehicle-treated hypoxia-exposed, and unhandled control.
- Mean arterial blood pressure, cardiac weight ratios, and plasma epinephrine levels were measured.
Main Results:
- Vehicle-treated rats exposed to episodic hypoxia showed a significant increase in mean arterial blood pressure (7.7 mm Hg).
- All other groups, including denervated hypoxia-exposed rats, exhibited a decrease in mean arterial pressure.
- Episodic hypoxia exposure increased left ventricle and septum to whole body weight ratio.
Conclusions:
- The peripheral sympathetic nervous system is essential for the development of persistent hypertension in response to repetitive episodic hypoxia.
- Targeting the sympathetic nervous system may offer therapeutic strategies for hypoxia-related cardiovascular changes.