Quantitative determination of monoamine neurotransmitters in rat brain homogenates using HPLC-MS/MS

Abstract

Relevance. Evaluation of the effect of drugs on neurotransmitter processes is an important component of pharmacodynamic studies. The quantitative determination of monoamine neurotransmitters in the brain structures of laboratory animals is an urgent task of pharmacology and physiology.Purpose of the study. Development of a method for the quantitative determination of serotonin, dopamine, norepinephrine, histamine and epinephrine in rat brain homogenates using HPLC-MS/MS.Methods. The isolation of neurotransmitters from the brain of rats was carried out by homogenizing the biomaterial with acetonitrile and hydrochloric acid. The extraction was purified by liquid-liquid extraction with chloroform and isopropanol. Monoamines were detected using an AB Sciex QTrap 3200MD mass spectrometer, chromatography was performed using an Agilent Technologies 1260 Infinity II HPLC. Methanol and deionized water were used as eluent.Results. Sample preparation consisted of centrifugation of the resulting homogenate, drying of the supernatant in a stream of nitrogen, dissolution of the precipitate in the mobile phase, and purification of the solution using a mixture of chloroform and isopropanol. An Agilent InfinityLab Poroshell 120 EC-C18 4.6×100 mm, 2.7 μm analytical column was used to separate monoamine neurotransmitters. The total time of the chromatographic analysis was 12 minutes, the retention time of norepinephrine, epinephrine, dopamine, serotonin, histamine was 2.8; 3.2; 5.4; 7.9; and 2.2 minutes, respectively. The analytical range of the technique was 25.0–5000.0 ng/g for epinephrine, histamine, and dopamine; 5.0–5000.0 ng/g for serotonin and 50.0–5000.0 for norepinephrine. To test the technique, we analyzed monoamine neurotransmitters in the striatum of intact Wistar rats.Conclusion. The developed bioanalytical HPLC-MS/MS method for the quantitative determination of monoamine neurotransmitters in the rat brain fully complies with the validation requirements. The metrological characteristics of the technique make it possible to estimate the content of norepinephrine, epinephrine, dopamine, serotonin, and histamine in the brain structures of rats with high accuracy.