Neurotransmitters are endogenous chemicals that enable neurotransmission. They transmit signals across a chemical synapse, such as in a neuromuscular junction, from one neuron (nerve cell) to another "target" neuron, muscle cell, or gland cell. Neurotransmitters are released from synaptic vesicles in synapses into the synaptic cleft, where they are received by receptors on other synapses.