Our Previous studies showed 2,4-toluene diisocyanates(TDI) may act on ligand gated ion channel receptors. The inhibition of calcium signaling in human adenocarcinoma cell through P2X purinoceptors was proved by the suppression on ATP-induced calcium rise with and without external Ca2+. Modulators of these ligand gated ion channels act on more than one type of receptor in other kind of cells. Similar to toluene, TDI may affect ligand-gated ion channel receptor superfamily members also, but in Hela cell, it acts 25-fold higher than 2,4-toluene diamine (TDA)-its major metabolite. We speculated that conjugation reaction of isocyanate groups, may be contributive to the suppression of calcium signaling in Hela cell. In this study, we monitored the physical characteristics about changes of the fragment associated with those receptors adducted by TDI conjugation from capillary liquid high performance chromatography (Calp-HPLC) coupled with electron spray ionization-quadruple/time of flight (ESI-Q-TOF) mass spectrometric study. As a highly active chemical, TDI plays many complicate roles in the stimulation of the abnormal physiological responses through the adductive reaction; including its disturbance of acetylcholine activity in most affected workers. Our results showed accompany with the suppression of the [Ca2+]c rise induced by the potent nicotinic ligand, epibatidine, in human epithelial cell line, we found changes in the tryptic peptides of associate receptors.

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