Intracerebral microdialysis during deep brain stimulation surgery.

Area of Science:

• Neuroscience
• Neurosurgery
• Biochemistry

Background:

• Deep brain stimulation (DBS) of the subthalamic nucleus (STN) effectively treats advanced Parkinson's disease.
• The precise mechanisms underlying STN DBS efficacy are not fully understood.
• Measuring neurotransmitter levels in the basal ganglia (BG) could elucidate DBS mechanisms but presents technical challenges.

Purpose of the Study:

• To assess the feasibility of using microdialysis during DBS surgery to measure extracellular neurotransmitter levels in the human basal ganglia.
• To investigate the technical challenges and potential of this combined approach for mechanistic studies.

Main Methods:

• Microdialysis guide cannulas were inserted into the STN or substantia nigra after microelectrode localization.
• Microdialysis probes were perfused with artificial cerebrospinal fluid, and extracellular fluid samples were collected.
• Dialysate samples were analyzed for glutamate, gamma-aminobutyric acid (GABA), and dopamine using high-pressure liquid chromatography (HPLC).

Main Results:

• Neurotransmitter levels (glutamate, GABA, dopamine) were reliably quantified in dialysate samples via HPLC.
• A steady-state baseline of neurotransmitter concentrations was achieved within approximately 30 minutes.
• The method demonstrated reliability in identifying and quantifying key neurotransmitters.

Conclusions:

• Microdialysis is a feasible technique for assessing neurotransmitter levels (glutamate, GABA, dopamine) in the human basal ganglia during DBS surgery.
• Establishing a steady-state baseline of neurotransmitter levels is achievable, supporting the value of intraoperative microdialysis.
• This approach provides a meaningful foundation for future research into the mechanisms of DBS.