Chemical Causes and Exacerbating Factors (pg 4)
These causes are illustrated in the chemical diagram. All can cause significant worsening: thus the essential need for ongoing environmental controls.
Chemical exposure can cause inflammation and neural sensitization:
- Pesticides, fungicides 78,79 and herbicides78,79 activate the NMDA receptor.78,80
- Pesticides such as organophosphates and carbamates over stimulate NMDA. This occurs because they inhibit acetylcholinesterase (a nerve cell messenger), and over stimulate muscarinic nerve receptors, which increase nitric oxide. When muscarinic receptors are too stimulated by pesticides, increased calcium is released within cells. This over stimulates NMDA receptors.
As discussed above, NMDA activation causes excess nitric oxide, producing neural sensitization.
- Pyrethroids Pesticides interfere with cell ability to keep out excess sodium. This harms cell electrical balance and activates NMDA receptors.81
- Formaldehyde activates NMDA.16,72 Formaldehyde also stimulates the brain vanilloid receptor. This receptor induces sensitization by activating the NMDA receptor83 and increasing nitric oxide, which then increases peroxynitrite and sets in motion neural sensitization.
Vanilloid receptor stimulation also increases release of immune substance P.84 Increased substance P is associated with reactive airway disease.85
- Petrochemicals (VOC’s, solvents) damage energy production (in mitochondria) and increase superoxide free radicals which increases peroxynitrite.86 This can increase tissue-damaging free radicals in the brain.87 Peroxynitrite also harms energy production.1,47 Repeated very low-level solvent exposure (e.g., toluene at 1 ppm; far below legally allowed exposure limits) can cause sensitization.88
- Carbon monoxide Carbon monoxide is released in all combustion: coal, gas, gasoline/diesel, wood, tobacco, and even natural products (beeswax and other candles) and “aromatherapy” (a medical oxymoron). Exposure to carbon monoxide even at “low levels” can increase nitric oxide and cause excess NMDA activity.89,90
- Irritants Petrochemicals and many other chemicals are irritants.90 Irritant exposure can cause inflammation. Repeated or high exposure can lead to chronic inflammation.73 Inflammation results in further elevated nitric oxide and damaging free radicals.
- Particles cause inflammation and increase nitric oxide. 4,16,91-94
Medical References (footnotes)--Neural Sensitization: The Key to Medical Treatment
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