Tonic Serotonin Measurements In Vivo Using N-Shaped Multiple Cyclic Square Wave Voltammetry

Area of Science:

• Electrochemistry
• Neuroscience
• Analytical Chemistry

Background:

• Serotonin is crucial for regulating mood, behavior, and various physiological processes.
• Accurate in vivo quantification of tonic serotonin is essential for understanding brain function and disorders.
• Existing voltammetric techniques face challenges with electrode fouling and selectivity.

Purpose of the Study:

• To develop and validate a novel voltammetric technique, N-shaped multiple cyclic square wave voltammetry (N-MCSWV), for in vivo serotonin quantification.
• To assess the sensitivity, selectivity, and fouling mitigation capabilities of N-MCSWV.
• To measure tonic extracellular serotonin levels in specific brain regions in rats.

Main Methods:

• Development of N-shaped multiple cyclic square wave voltammetry (N-MCSWV).
• Application of N-MCSWV with PEDOT:Nafion-coated carbon fiber microelectrodes.
• In vivo measurements in the substantia nigra pars reticulata of urethane-anesthetized rats.
• Pharmacological challenges using synaptic reuptake inhibitors.

Main Results:

• N-MCSWV demonstrated high sensitivity and selectivity against common interfering species.
• Fouling effects were significantly mitigated compared to conventional methods.
• A tonic serotonin concentration of 52 ± 5.8 nM was determined in rat substantia nigra pars reticulata.
• Pharmacological tests confirmed the selective detection of tonic serotonin.

Conclusions:

• N-MCSWV is a robust and novel voltammetric technique for the analytical quantification of serotonin in vivo.
• The technique enables continuous monitoring of tonic serotonin concentrations, aiding research into brain function and psychiatric disorders.
• N-MCSWV offers a significant advancement for electrochemical sensing in complex biological environments.