What does Low Glutamate do to the Body (Signs/Symptoms of low Glutamate in Periphery/Outside of the Brain/Extremeties)

I will be making another article directly after this with a compare and contrast of mind-body symptoms. This article is meant to expand beyond just low NMDA receptor activity - and instead aims to define low glutamate symptoms within the body or in peripheral tissues/extremities.

Glutamate is the most abundant neurotransmitter in the human nervous system. It is essential to cell energy production; including the mitochondria - and is the major facilitator of both nitric oxide production as well mobilizing calcium ions, providing the vital means by which calcium is taken up by both nerve cells and non-neural sites. 



Thus, this article is essentially showing the symptoms of glutamate deficiency outside of the psychogenic responses that would be correlated with brain glutamate deficiency, and hopes to provide a separate analysis which is not fettered or disturbed by conflicting systems / reports. 

SYMPTOMS OF LOW GLUTAMATE IN THE BODY/PERIPHERY

• High Blood Pressure or Low Blood Pressure(1) (2) (3). 

** Because glutamate is necessary for nitric oxide production, low levels may lead to high blood pressure , however, a net reduction in nervous system activity may paradoxically lead to low blood pressure - thus either are possible. **

• Lack of muscle-contractions during workouts/heavy lifting.(4) (5) (!)
• Severe constipation, slowed intestinal transit, lack of bowel contractions(6)(7)(8).

** Glutamate plays a large role and is in close coordination with serotonin, especially in the gut - serotonin can trigger gut contraction and bowel movement through 5-HT4 receptors while glutamate can activate the cGMP pathway which then activates the 5-HT4 serotonin signaling pathway. Essentially this comes down to calcium-nitric oxide reactions which allow for normal bowel function.**

• Loss of appetite(9)(10)(11).

**This assertion is from both straight scientific evidence demonstrating glutamate as playing both a permissive and facilitative role in food intake, as well as demonstrated by drugs and supplements which inhibit glutamate release often producing a loss of appetite.**

• Decreased sensitivity to pain / lack of pain sensation(12)(13)(14). 
• Erectile Dysfunction (vascular and neural) (15) (16) (17)
• Muscle Weakness(18)(19).
• Loss of or weakening of taste buds/taste perception(20)(21).
• Poor respondency/no response to nitric oxide boosters / N.O products/supplements(22)(23).

** If you are asking "why do I not respond to nitric oxide boosting supplements" - low glutamate may be the reason - glutamate is necessary for nitric oxide synthesis - thus substrates and precursors such as arginine or citrulline or even PDE-5 inhibitors may not do much if glutamate is deficient.**

"How to become sensitive to nitric oxide products/boosters again"