neurotransmitter« Back to Glossary Index
A neurotransmitter is a chemical “messenger” that allows nerve cells to “talk” with other nerve cells and with muscles, organs or other tissue. This chemical is released from one nerve cell, or neuron, at a specialized location (synaptic site), or junction. It then spreads, or diffuses, across a narrow gap, or cleft, to affect one or sometimes two other neurons on the other side of the cleft (postsynaptic), a muscle cell or another effector cell. A neurotransmitter influences a neuron in one of 3 ways: excitatory, inhibitory or modulatory.