The term catecholaminergic cell groups refers to collections of neurons in the central nervous system that have been demonstrated by histochemical fluorescence to contain one of the neurotransmitters dopamine or norepinephrine. Thus, it represents the combination of dopaminergic cell groups and noradrenergic cell groups ( Kitahama-19946 ). Some authors include in this category 'putative' adrenergic cell groups, collections of neurons that stain for PNMT, the enzyme that converts norepinephrine to epinephrine (adrenalin) ( Kitahama-1994 ).