Final answer:
The presynaptic neuron releases neurotransmitters into the synaptic cleft and the postsynaptic neuron has receptors that initiate a signal when specific neurotransmitters bind to them.
Step-by-step explanation:
The presynaptic neuron releases neurotransmitter into the synaptic cleft; the postsynaptic neuron contains receptors that, when filled, initiate a signal. In neuronal communication, the presynaptic neuron transmits a signal down its axon to the terminal buttons, where neurotransmitters are then released into the synaptic cleft. The synaptic cleft is the minute space between the presynaptic and postsynaptic neurons. Neurotransmitters travel across this cleft and bind to specific receptors on the dendrite of the adjacent (postsynaptic) neuron.
These receptors, which are protein structures, have unique shapes that match the shapes of different neurotransmitters, ensuring the correct neurotransmitters bind to the correct receptors. Therefore synaptic transmission is critical for neural communication involving both the presynaptic neuron that releases the neurotransmitter into the synaptic gap and the postsynaptic neuron that receives the signal through its receptors.