A related study by the same research team challenges another theory about where in the brain this dopamine action occurs. Dopamine is a neurotransmitter, a chemical that carries messages from one nerve cell, or neuron, to another or from one functional section of the brain to another. This neurotransmitter is associated with body movement, awareness, judgment, motivation, and pleasure.
Researchers believe it is responsible for the addictive effects of drugs such as cocaine.
Dopamine flows from neurons into the synapses, or spaces between neurons, to form a temporary link that serves to transmit signals between neurons. Then, normally, after it has transmitted its signal to the neighboring neuron, it vacates these spaces, returning to the same neuron that released it in a recycling process called reuptake. The neurotransmitter dopamine transmits brain signals by flowing from one neuron into the spaces between neurons and attaching to a receptor on another neuron. Normally, dopamine then is recycled back into the transmitting neuron by a transporter molecule on the surface of the neuron. But if cocaine is present, the drug attaches to the transporter and blocks the normal recycling of dopamine, causing an increase of dopamine levels in the spaces between neurons that leads to euphoria.