Microdialysate analysis of monoamine neurotransmitters--a versatile and sensitive LC-MS/MS method

Area of Science:

• Neuroscience
• Analytical Chemistry
• Pharmacology

Background:

• Monoamine neurotransmitters like dopamine, norepinephrine, and serotonin play critical roles in brain function.
• Accurate quantification of these neurotransmitters in complex biological matrices is essential for understanding neurological processes and drug effects.
• Existing methods may lack the sensitivity or throughput required for detailed microdialysis studies.

Purpose of the Study:

• To develop and validate a sensitive, high-performance liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS) method.
• To enable simultaneous determination of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) in rat brain microdialysate.
• To apply the validated method for monitoring neurotransmitter changes following amphetamine administration.

Main Methods:

• Amine derivatization using (5-N-succinimidoxy-5-oxopentyl)triphenylphosphonium bromide (SPTPP) under mild conditions.
• High-performance liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS) utilizing selected reaction monitoring (SRM) mode.
• Analysis of neurotransmitter concentrations in rat brain microdialysate samples from the striatum region.

Main Results:

• Achieved a lower limit of quantification (LLOQ) of 30 pM with high accuracy (≤3.80%) and precision (±7.39% CV) for DA, NE, and 5-HT.
• Demonstrated excellent linearity (R>0.99) over a wide concentration range (30-50,000 pM).
• Successfully monitored neurotransmitter concentration changes in rat striatum microdialysate after amphetamine administration.

Conclusions:

• The developed LC/MS/MS method is sensitive, accurate, and precise for simultaneous neurotransmitter determination.
• Amine derivatization with SPTPP enhances chromatographic properties and detection limits.
• The method is suitable for in vivo microdialysis studies investigating neurochemical changes in the brain.