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Increased plasma normetanephrine in spontaneously hypertensive rats
Clinical and Experimental Hypertension
|February 1, 1980
Summary
Spontaneously hypertensive rats (SHR) show elevated plasma epinephrine and normetanephrine levels compared to controls. This suggests enhanced sympathetic activity contributes to high blood pressure in SHR, as normetanephrine reflects norepinephrine reaching target cells.
Area of Science:
- Physiology
- Pharmacology
- Hypertension Research
Background:
- Spontaneously hypertensive rats (SHR) are a widely used model for studying human hypertension.
- Sympathetic nervous system activity plays a crucial role in regulating blood pressure.
Purpose of the Study:
- To investigate plasma catecholamine and normetanephrine levels in SHR compared to normotensive Wistar Kyoto (WKy) rats.
- To explore the relationship between sympathetic function and blood pressure elevation in SHR.
Main Methods:
- Measurement of plasma norepinephrine and epinephrine concentrations via radioenzymatic assay.
- Quantification of total plasma normetanephrine using a specific radioenzymatic assay.
- Comparison of these levels between 11 SHR and 11 age/sex-matched WKy rats.
Main Results:
- Plasma epinephrine levels were significantly higher in SHR (1079 pg/ml) than in WKy rats (695 pg/ml) (p < 0.05).
- Total plasma normetanephrine concentrations were markedly elevated in SHR (1825 pg/ml) compared to WKy rats (535 pg/ml) (p < 0.02).
- Plasma norepinephrine levels did not differ significantly between SHR and WKy rats.
Conclusions:
- Elevated plasma normetanephrine in SHR suggests increased norepinephrine release and/or extraneuronal uptake and metabolism.
- These findings support the hypothesis that enhanced sympathetic nervous system activity contributes to the elevated blood pressure observed in spontaneously hypertensive rats.