Claim: Dopamine sends signals to other nerve cells in the brain.

Neurotransmitters , also known as chemical messengers , are endogenous chemicals that enable neurotransmission . They transmit signals across a chemical synapse , such as a neuromuscular junction , from one neuron -LRB- nerve cell -RRB- 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 the target cells . Many neurotransmitters are synthesized from simple and plentiful precursors such as amino acids , which are readily available from the diet and only require a small number of biosynthetic steps for conversion . Neurotransmitters play a major role in shaping everyday life and functions . Their exact numbers are unknown , but more than 100 chemical messengers have been uniquely identified .