Neurotransmitter sampling and storage for capillary electrophoresis analysis

Area of Science:

• Neuroscience
• Analytical Chemistry
• Biochemistry

Background:

• Quantitative analysis of signaling molecules from single cells and tissues is vital.
• Method validation is essential for accurate measurement of low-weight, biologically active molecules.
• Challenges exist in preserving the integrity of labile biomolecules like serotonin and dopamine during storage.

Purpose of the Study:

• To investigate optimal storage strategies for single neurons and neuronal tissues.
• To determine the stability of key signaling molecules (serotonin, dopamine, citrulline) under various storage conditions.
• To establish reliable protocols for preserving sample composition before analysis.

Main Methods:

• Capillary electrophoresis with laser-induced fluorescence detection was employed.
• Homogenized ganglia samples from *Pleurobrain-Chae californica* were analyzed.
• Storage conditions tested included room temperature, rapid freezing, and preservation with ascorbic acid.

Main Results:

• Arginine and citrulline showed stability at room temperature for days.
• Catecholamines and indolamines (dopamine, serotonin) degraded by 20% within 10 hours at room temperature.
• Freezing or ascorbic acid preservation retained >80% dopamine and ~70% serotonin after five days.
• Combined ascorbic acid preservation and freezing at -20°C ensured complete stability of serotonin and dopamine for at least five days.
• An optimal protocol (freezing within 2 hours) allowed storage for over four weeks with <10% loss of serotonin and dopamine.
• Single cell samples required analysis within 4 hours to minimize metabolite loss.

Conclusions:

• Sample preservation timing is critical for maintaining the original composition of biological samples.
• Optimal storage protocols involving rapid freezing and ascorbic acid are essential for accurate quantification of neurotransmitters.
• Specific storage requirements differ for bulk tissue homogenates versus nanoliter-volume single cell samples.