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66

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

Eisenhofer, Graeme; Lenders, Jacques W.M.;

Timmers, Henri; Mannelli, Massimo;

Grebe, Stefan K. et al. (2011)

Measurements of Plasma Methoxytyramine,

Normetanephrine, and Metanephrine as

Discriminators of Different Hereditary

Forms of Pheochromocytoma

Clin. Chem.

vol. 57 (3) p. 411-420

Ossowska, Krystyna; Wardas, Jadwiga;

Kuter, Katarzyna; Nowak, Przemysław;

Dabrowska, Joanna et al.

Influence of paraquat on dopaminergic trans-

porter in the rat brain.

Pharmacological reports : PR

vol. 57 (3) p.

330-5

Sotnikova TD, Beaulieu J-M, Espinoza S,

Masri B, Zhang X, et al. (2010)

The Dopamine Metabolite

3-Methoxytyramine Is a

Neuromodulator.

PLoS ONE 5(10): e13452. doi:10.1371/

journal.pone.0013452

Young, William F (2006)

Paragangliomas: clinical overview.

Annals of the New York Academy of Sciences

vol. 1073 p. 21-9

Norepinephrine

Norepinephrine is secreted by the

adrenal gland. Norepinephrine is the

primary neurotransmitter for post-gan-

glionic sympathetic adrenergic nerves

(that synapse in target cells). The nore-

phinephrine signaling system regulates

the endocrine and autonomic nervous

systems. It is the principal neurotrans-

mitter in sympathetic nerve endings.

The sympatho-adrenal system plays an

important role in the regulation of blood

pressure, glucose, sodium concentra-

tions and other physiological and met-

abolic processes. Norepinephrine binds

to adrenergic receptors; the binding of

norepinephrine to the receptors primar-

ily stimulates the sympathetic nervous

system. Norepinephrine levels may help

regulate attention, cognition and sleep.

Research indicates that norepinephrine

signaling may contribute to:

Maintaining focus and attention

(vigilance)

Filter weak stimuli and enhance

moderate stimuli, and enhance

responses to strong stimuli (stimuli

are detectable changes in internal or

external environment)

Information processing and

executive functions (reasoning,

learning, problem-solving)

Memory storage and retrieval

(particularly memories associated

with strong emotion)

“Fight or flight” stress responses

Disregulation of norepinephrine sig-

naling may contribute to mood and bi-

polar disorders. Evidence indicates that,

in the central nervous system (CNS)

norepinephrine metabolites are lower

in depressed patients and higher during

the manic phase of bipolar patients.

Medications that prevent norepineph-

rine reuptake or inhibit norepinephrine

metabolism have been shown to im-

prove depressive symptoms.

Effects:

Decreased

norepinephrine may be

associated with rare, inherited condi-

tions such as dopamine beta-hydrox-

ylase (D

H) enzyme deficiency and

Menkes disease. Elevated dopamine

(and metabolites) and low norepineph-

rine levels may occur due to D

H en-

zyme dysfunctions. Multiple single nu-

cleotide polymorphisms (SNPs) have

been identified in the genes coding for

D

H and are being evaluated for asso-

ciations in attention, behavior, psychi-