What do glutamate and GABA each do to the same neuron's membrane? · Grey Matter

Glutamate opens AMPA channels that let sodium in, so the membrane moves toward threshold within a millisecond; if the cell is already depolarised, NMDA receptors also lose their magnesium block and admit calcium.

What do glutamate and GABA each do to the same neuron's membrane?

Glutamate opens AMPA channels that let sodium in, so the membrane moves toward threshold within a millisecond; if the cell is already depolarised, NMDA receptors also lose their magnesium block and admit calcium. GABA works the other way: GABA-A receptors open chloride channels that hold the membrane at or below rest and short-circuit excitatory currents, and GABA-B receptors, more slowly, open potassium channels through G proteins. The neuron fires or stays silent according to the running sum of the two, which is why the same cell can be pushed either way within a few milliseconds.