The neurotransmitters are chemical messengers capable of transmitting a signal from a given nerve cell across biological junctions named 'synapses' to target cells such as, for example, other nerve cells (e.g., neurons). In the cell, the neurotransmitters are transported into internal vesicles that are fused with the cell membrane to release them in the synaptic cleft by the process of exocytosis. Subsequently, the neurotransmitters bind to cell receptors localized on the postsynaptic membrane and thus trigger responses in postsynaptic cells. For example, glutamate is a neurotransmitter capable of exciting nerve cells by binding to a transmitter-gated ion channel called N-methyl-D-aspartate (NMDA).
