Postsynaptic Potentials

Postsynaptic potentials in sensory receptors are gradedpotentials (graded weak-to-strong), which indirectly generate the nerve impulse—their function being to initiate/inhibit action potentials. They are caused by presynaptic neurons releasing neurotransmitters from the axon terminal into the synaptic cleft. The neurotransmitters bind to receptors on the postsynaptic terminal, which may be a neuron or a muscle cell.