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[The factors affecting plasma catecholamines concentration in rats and man]
Nihon Yakurigaku Zasshi. Folia Pharmacologica Japonica
|January 1, 1984
Summary
This study compared three methods for measuring plasma catecholamines, finding REA suitable for small samples. Norepinephrine levels increased with age and blood pressure in hypertensive rats, particularly with cerebral hemorrhage.
Area of Science:
- Biochemistry
- Pharmacology
- Physiology
Background:
- Catecholamines, such as norepinephrine, epinephrine, and dopamine, are crucial neurotransmitters and hormones.
- Accurate measurement of plasma catecholamine concentrations is vital for understanding various physiological and pathological conditions.
Purpose of the Study:
- To compare the sensitivity, reproducibility, and sample volume requirements of three methods: High-Performance Liquid Chromatography with Thermal Energy Analyzer (HPLC-THI), High-Performance Liquid Chromatography with Electrochemical Detection (HPLC-ECD), and Radioenzymatic Assay (REA).
- To investigate factors influencing plasma catecholamine measurements, including blood withdrawal volume and age.
- To examine plasma catecholamine levels in different rat models, focusing on age-related changes and hypertension.
Main Methods:
- Simultaneous measurement of rat and human plasma catecholamines using HPLC-THI, HPLC-ECD, and REA.
- Assessment of method sensitivity, reproducibility, and required sample volumes.
- Evaluation of the impact of blood withdrawal volume on catecholamine levels.
- Analysis of plasma catecholamine concentrations in Wistar Kyoto rats and stroke-prone spontaneously hypertensive rats (SHRSP) concerning age, sex, blood pressure, and cerebral hemorrhage.
Main Results:
- HPLC-THI, HPLC-ECD, and REA demonstrated identical sensitivity and reproducibility for norepinephrine and epinephrine.
- REA required smaller sample volumes compared to HPLC methods.
- HPLC-ECD was preferred for determining plasma dopamine concentration.
- Withdrawing 5 ml of blood significantly increased plasma catecholamine levels in rats, as measured by REA.
- Plasma norepinephrine increased with age in SHRSP but not in Wistar Kyoto rats.
- SHRSP exhibited higher norepinephrine levels than females, correlating with blood pressure.
- Cerebral hemorrhage in SHRSP was associated with significantly elevated plasma norepinephrine.
Conclusions:
- The choice of method for plasma catecholamine determination depends on sample size and catecholamine concentration.
- Blood withdrawal volume is a critical factor affecting measured catecholamine levels.
- Age and hypertension significantly influence plasma norepinephrine concentrations in specific rat models, with implications for cardiovascular and neurological health.