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

101

Multiple receptor subtypes

NMDA R1 A-G and NMDA R2

A-D

Preclinical studies indicate that

NMDA glutamatergic signaling may

influence the formation of conditioned

fear memories. Abnormal baseline

and fear-potentiated startle symptoms

have been observed in patients with

post-traumatic stress disorder, suggest-

ing that disturbed glutamate signal-

ing may contribute to anxiety. Animal

studies indicate that chronic stress

down-regulates NMDA and AMPA re-

ceptor expression in the brain second-

ary to the stimulation of glucocorticoid

receptors. The down-regulation of the

glutamate receptors affected glutamate

signaling and memory function in the

experimental animals.

Metabotropic glutamate receptor

(mGluRs) activity occurs primarily via

second messenger signaling through cy-

clic adenosine monophosphate (cAMP)

or phosphorylation of proteins. mGluRs

are G-protein coupled receptors similar

to dopamine, norepinephrine or sero-

tonin receptors.

They are divided into three types:

Type I

post-synaptic

excitatory

concentrated in amygdale, thalamus,

hippocampus

mGluR1 and mGluR5

Type II

pre-synaptic glutamate release

inhibitory

mGluR2 and mGluR3

Type III

primarily pre-synaptic (glutamate

and GABA neurons)

neuromodulators in brain

mGluR 4 and mGluR 6-8

Some anxiety symptoms have been

associated with changes in mGluRs.

Metabolomic type III receptors are

found in nerve pathways commonly

overactive in Parkinson’s disease. Animal

studies indicate that metabolomic type

I and II glutamate receptors may con-

tribute to heart rate and blood pressure

regulation.

Consider:

Glutathione status

( Glutathione; erythrocytes )

Oxidative stress

( DNA Oxidative Damage Assay/8-OHdG )

Methionine metabolism and

methylation pathways

( Plasma Methylation Profile, DNA Methylation Pathway )

Nutrient element (mineral) and

manganese status

( RBC Elements )

Digestion and absorption

( Comprehensive Stool Analysis

)

References:

Akiba, Yasutada; Kaunitz, Jonathan D

(2009)

Luminal chemosensing and upper gastroin-

testinal mucosal defenses

Am J Clin Nutr

vol. 90 (3) p. 826S-831

Bridges, Richard; Lutgen, Victoria; Lobner,

Doug; Baker, David A (2012)

Thinking outside the cleft to understand

synaptic activity: contribution of the cys-

tine-glutamate antiporter (System xc-)

to normal and pathological glutamatergic

signaling.