PRESYNAPTIC AND
POSTSYNAPTIC INHIBITION
Inhibitory synapses modulate
neuronal excitability. Presynaptic inhibition (left) and postsynaptic
inhibition (right) are shown in relation to a motor neuron.
Postsynaptic
inhibition causes local
hyperpolarization at the postsynaptic site. Presynaptic inhibition involves the
depolarization of an excitatory axon terminal, which decreases the amount of
Ca2+ influx that occurs with depolarization of that excitatory
terminal, thus reducing the
resultant EPSP at the postsynaptic site.
