A class of NEUROTRANSMITTERS that possess a single amine (-NH2) group. The term MONOAMINERGIC indicates possession of monoamines, as in MONOAMINERGIC neurons or monoaminergic systems. Monoamines consist of a central ringed structure with a side chain.
There are two groups of monoamines, the CATECHOLAMINE group, in which the ringed structure is a catechol, and the INDOLEAMINE group, in which the ringed structure is an indole. The most well-known monoamines are the catecholamines DOPAMINE, NORADRENALINE (known as norepinephrine in the United States) and ADRENALINE (epinephrine) and the indoleamines SEROTONIN and MELATONIN. The monoamines dopamine, noradrenaline, and serotonin are localized in nuclei in the MIDBRAIN and HINDBRAIN, and send long projections to the forebrain where they are thought to play a critical role in modulation of neuronal activity. Functionally they have been associated with cognition, EMOTION, MOTIVATION and motor activity (see LOCOMOTION) and, pathologically, with DEPRESSION, SCHIZOPHRENIA and PARKINSON’S DISEASE.
