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Sympathoadrenal system is critical for structural changes in genetic hypertension
Hypertension (Dallas, Tex. : 1979)
|August 1, 1993
Summary
Sympathetic nerves and adrenal glands drive hypertension and cardiovascular changes in spontaneously hypertensive rats. Blocking alpha-adrenergic receptors with prazosin prevents these effects, highlighting their critical role.
Area of Science:
- Cardiovascular Physiology
- Pharmacology
- Hypertension Research
Background:
- Spontaneously hypertensive rats (SHR) exhibit elevated blood pressure and cardiovascular structural changes compared to Wistar-Kyoto (WKY) rats.
- The roles of sympathetic nerves and adrenal glands in mediating these differences are not fully elucidated.
Purpose of the Study:
- To investigate the contribution of sympathetic nerves and adrenal glands to hypertension and cardiovascular hypertrophy in SHR.
- To determine the effects of alpha-adrenergic receptor blockade on these processes.
Main Methods:
- Rats (SHR and WKY) underwent sympathectomy (SX) and/or prazosin treatment (SXP).
- Measurements included norepinephrine concentrations, left ventricular weight, and hindquarter vascular resistance.
- Studies were conducted at 4, 8, 21, and 35 weeks of age.
Main Results:
- Sympathectomy and prazosin depleted tissue norepinephrine but increased adrenal norepinephrine.
- SHR showed greater left ventricular weight and vascular resistance than WKY rats.
- Prazosin treatment completely prevented hypertension, left ventricular hypertrophy, and vascular changes in SHR.
Conclusions:
- Sympathetic nerves and adrenal glands are primary sources of alpha-adrenergic stimulation in developing SHR hypertension.
- These factors significantly contribute to the cardiovascular structural differences observed between SHR and WKY rats.
- Alpha-adrenergic receptor blockade effectively prevents the development of hypertension and associated pathologies in SHR.