Real-time multisite observation of glutamate release in rat hippocampal slices

A multichannel glutamate sensor was fabricated that consists of enzyme modified electrodes and has a high sensitivity and selectivity to glutamate. We placed a rat hippocampal slice on the sensor and monitored the current at four electrodes resulting from the stimulation with muscimol, a γ-aminobutyric acid A (GABA A) receptor agonist. We obtained different glutamate concentration increases at the different positions, suppressed by bicuculline, a GABA A receptor antagonist. This demonstrated that the sensor can monitor the glutamate released via GABA A receptors pathways, and the difference in the concentrations may indicate differences in the distribution of GABA A receptor as well as diverse receptor functions. This multichannel sensor may be useful for non-invasive, real-time monitoring of glutamate distribution, which would make it a valuable tool for pharmacological analysis.