Amperometric Detection of Dopamine Exocytosis from Synaptic Terminals

Excerpt

Dopamine (DA) was discovered as the precursor of the neurotransmitter norepinephrine in 1957 (Montagu 1957). Carlsson demonstrated that DA levels in the striatum were much higher than in the rest of the brain despite its low level of norepinephrine, suggesting that DA was not merely a norepinephrine precursor but was itself a neurotransmitter (1959) (Carlsson 1959). Subsequently, DA’s role as a neurotransmitter has been confirmed and populations of DA neurons have been identified in various regions of the central nervous system (olfactory bulb, substantia nigra, ventral tegmental area, and the retina) and the periphery (enteric nervous system of the gut). These neurons are involved in modulating intestinal motility, the sense of smell, light sensitivity, and control of fine motor movements. They are also integral to higher brain functions such as salience, euphoria, pleasure and appetitive and consummatory aspects of reward. Their demise or dysfunction plays vital roles in neuropathologies such as Parkinson’s disease, schizophrenia and depression. Thus, understanding how DA neurons function normally in neurotransmission and in pathological processes is essential for elucidating their roles in behavior and disease.