A Technique to Assess the Inhibitory Effect of Toxin Exposure on Miniature Excitatory Postsynaptic Currents (mEPSCs)

Treat neuronal cultures with increasing concentrations of a test toxin.

The toxin enters the cells and is released into the cytosol.

Depending on its potential, the toxin may prevent vesicular fusion, inhibiting neurotransmitter release.

Replace the medium with a buffer containing specific neuropharmacological compounds to block neuronal action potentials.

Place the culture dish on an electrophysiology stage. To start recording, connect a neuron soma with a pipette containing a recording electrode.

Apply steady negative pressure to aspirate a small membrane portion, forming a gigaseal, a tight seal that ensures minimal interference during recording.

Maintain a constant membrane voltage to measure neuronal currents.

Apply negative pressure pulses to rupture the membrane, establishing direct contact between the neuron and the pipette.

Record the currents produced in the neuron due to the uptake of neurotransmitters, termed mEPSCs.

A decrease in mEPSC frequency with increased toxin exposure indicates the inhibition of neurotransmitter release.