Neurotransmitter receptors are located on the cell surface of specific ligands, post-synaptic cells and sometimes pre-synaptic cells. While they are most commonly found in the nervous system, they are also present on some muscle and immune tissues.
Neurotransmitter receptors receive signals and excite or inhibit a cellular process in response. As each neuron connects with more than 15,000 other neurons, the majority of neurotransmitter receptors produce excitatory responses. After receiving a neurotransmitter, the receptor usually triggers an action potential, which then leads to a cellular process elsewhere. Most are G protein-coupled receptors, which span across the cell's surface more than once.