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Functional Assessment of Urinary Neuro-biogenic Amines—A COMPREHENSIVE GUIDE 

53

Neurotransmitter Analytes:

Dopamine

The catecholamine, dopamine (DA),

plays a primary role in the control of

motor, cognitive, behavioral (emotion-

al) and endocrine functions in the cen-

tral nervous system (CNS). Dopamine

nerve pathways in the brain affect vol-

untary movements, feeding, behavior-

al affect, emotion, reward signaling,

attention, speech, memory, learning

and sleep. Too much or too little dopa-

mine may affect memory and cognition.

Dopamine signaling controls hormone

release from the anterior pituitary gland.

Dopamine serves as a neurotransmit-

ter in the CNS, in the adrenal glands,

and in autocrine/paracrine signalling

throughout the body. Dopamine is an

important regulator of systemic blood

pressure and gastrointestinal functions.

Impairment in the central dopamine

pathways and metabolism has been sug-

gested as a factor in the pathogenesis

of restless leg syndrome (RLS). Animal

studies indicate that dopamine release

in the brain correlates to the calorie load

of food ingested or infused into the gas-

trointestinal tract. Dopamine signaling

also affects the retina, sense of smell and

hormone status.

Dopamine may also function as a

neuromodulator, as dopamine modu-

lates calcium signaling. The flow of cal-

cium and other ions into and out of neu-

rons changes the action potential within

the nerve. Dopamine is an inhibitory

neurotransmitter and dopamine calcium

signaling may be the mechanism that

counteracts the damaging effects of ex-

cess glutamate (excitotoxicity) in the

brain.

Dopamine signaling contributes to

motivated behavior. Animal studies in-

dicate that different areas of the brain

are involved in different aspects of mo-

tivational activity (such as feeding) and

reward behavior. Dopamine signaling

may play a role in addictive behaviors;

drugs such as cocaine and amphetamine

have been shown to increase dopa-

mine concentrations in nerve synapses.

Disregulation of dopamine signaling has

been associated schizophrenia, attention

deficit, and neurodegenerative diseases

such as Parkinson’s.

Effects:

Decreased

dopamine release in the

motor pathway, or a dysfunction of do-

pamine receptors, leads to movement

disorders. The loss of dopamine neu-

rons is associated with neurodegener-

ative disorders such as Parkinson’s dis-

ease, and results in motor symptoms