An excitatory neurotransmitter such as GABA will open up ion channels in the

postsynaptic membrane. This will allow sodium (Na+) and potassium (K+) ions

to follow into the dendrite, increasing the membrane potential closer to 0 mV,

thereby increasing the likelihood for an action potential to occur. Similarly, an

inhibitory neurotransmitter will open up the ion channels for chloride ions (Cl–) to

flow in.

The effect of the inhibitory neurotransmitter on the postsynaptic membrane is to