Dopamine

Dopamine is an excitatory and inhibitory neurotransmitter, depending on the dopaminergic receptor it binds to. It is derived from the amino acid tyrosine. Dopamine is the precursor to norepinephrine and epinephrine, which are all catecholamines. The function of dopamine is diverse but plays a large role in the pleasure/reward pathway (addiction and thrills), memory, and motor control. Dopamine, like norepinephrine and epinephrine, is stored in vesicles in the axon terminal. Dopamine plays a significant role in the cardiovascular, renal, hormonal, and central nervous systems. The dopaminergic neurons have dendrites that extend into various regions of the brain, controlling different functions through the stimulation of adrenergic and dopaminergic receptors (D1 –D5). Common symptoms with low dopamine levels are loss of motor control, addictions, cravings, compulsions, and loss of satisfaction. When dopamine levels are elevated symptoms may manifest in the form of anxiety or hyperactivity. Some therapies utilize L-DOPA for parkinsonian symptoms which can also cause elevations in dopamine.