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 gamma-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.