In this chapter, the authors continue to explore neuronal communication. They discuss first how arrival of an action potential at the presynaptic terminal triggers neurotransmitter release and then how neurotransmitters affect postsynaptic cells. This process, called synaptic transmission, results in information transmission from the presynaptic cell to the postsynaptic cell across the chemical synapse. Finally, they discuss the electrical synapse, an alternative to the chemical synapse. They addressed the basic cell biological and electrical properties of neurons that are required to understand how molecules, organelles, and action potentials get to axon terminals. Intercellular communication mediated by chemical and electrical synapses is the foundation of all nervous system functions. It examines more examples to highlight the diverse outcomes of G-protein-coupled receptor (GPCR) signaling. Indeed, all signaling events they had discussed so far are associated with built-in termination mechanisms.