The vanilloid receptor as a putative target of diverse chemicals in multiple chemical sensitivity.

The vanilloid receptor (TRPV1 or VR1), widely distributed in the central and peripheral nervous system, is activated by a broad range of chemicals similar to those implicated in Multiple Chemical Sensitivity (MCS) Syndrome. The vanilloid receptor is reportedly hyperresponsive in MCS and can increase nitric oxide levels and stimulate N-methyl-D-aspartate (NMDA) receptor activity, both of which are important features in the previously proposed central role of nitric oxide and NMDA receptors in MCS. Vanilloid receptor activity is markedly altered by multiple mechanisms, possibly providing an explanation for the increased activity in MCS and symptom masking by previous chemical exposure. Activation of this receptor by certain mycotoxins may account for some cases of sick building syndrome, a frequent precursor of MCS. Twelve types of evidence implicate the vanilloid receptor as the major target of chemicals, including volatile organic solvents (but not pesticides) in MCS.

Acute toxicity of marking pen emissions.

To evaluate complaints of adverse reactions to marking pen emissions, groups of mice were exposed for 1 h to the emissions of 8 brands of felt-tip markers or white-board cleaner. Pneumotachographs and a computerized version of ASTM E-981 test method were used to measure changes in respiration. Sensory irritation (SI), pulmonary irritation (PI), and/or air flow limitation (AFL) of differing intensities were documented with each of the eight brands tested. At the peak of the effects, the largest SI was observed with pen F (72% of the breaths); the largest PI occurred with pen D (13% of the breaths), and the largest AFL was seen with pen F (25% of the breaths). Pens G and H produced minimal SI, PI, or AFL. A functional observational battery was used to screen for signs of neurotoxicity. Emissions from all eight of the pens produced behavioral abnormalities such as altered posture and gait, tremors, falling, and hyperactivity. The exposure concentrations were similar to the total volatile organic compounds (TVOC) values near marking pens in actual use. Gas chromatography identified mixtures of alcohols, acetates, and/or ketones. Exposures to white-board cleaner solution resulted in similar toxicity ( SI, PI, AFL, and neurotoxicity). These results document that some marking pens and white-board cleaner emit mixtures of chemicals that can produce acute respiratory toxicity and acute behavioral abnormalities in normal mice. These results provide a toxicological explanation for some of the human complaints concerning respiratory and neurological reactions to marking pen emissions.