The signals "catch a ride" on chemicals called neurotransmitters that drift between the synapses in a nerve. Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane in the axon terminal, on the presynaptic side of a synapse. They are released into and diffuse across the synaptic cleft, where they bind to specific receptors in the membrane on the postsynaptic side of the synapse. Release of neurotransmitters usually follows arrival of an action potential at the synapse, but may also follow graded electrical potentials.
Electrical impulses are passed across a synapse with the help of neurotransmitters. The neurotransmitter moves across the synapse and binds to proteins on the neuron membrane that is supposed to receive the impulse. The proteins are the ones that receiver the impulses directly.