| As a main indoor air pollutant, formaldehyde is very harmful. One of the harmful effects is airway irritation or airway neurogenic inflammation which results in sick building syndrome (SBS), multiple chemical sensitivity (MCS) and so on. Since indoor air formaldehyde pollution is getting more serious than before people take more attention on it. But the molecular mechanism of formaldehyde on evoked airway irritation is not clear. However, there are few of the hypotheses about it, for example, Nielsen hypothesis, which explain how formal dehyde and other air contamination beget neurogenic inflammation. Our task at present is testifying if the hypothesis is right or not .Activating of the capsaicin receptor is a important tache in Nielsen hypothesis, it might be used for testifying. But at that time capsaicin receptor was not cloned, so the condition for studying the hypothesis was immature. In 1997 cloned capsaicin receptor brought spark to studying Nielsen hypothesis, and Dr. D.J. Julius of California university, who cloned the receptor, donates of vanilloid receptor 1 (VR1) cDNA to us so as to our studying work begin.At first, the VRl-cDNA plasmids were transformed into TG1 R. coli to enlarge VRl-cDNA; then the plasmids were extracted and cut off with enzymes; subsequently, VRl-cDNAs were transcribed into VRl-inRNA by T7 or SP6 polymerase in vitro, following VRl-mRNAs were injected into Xenopus laevis oocyte to express into VR1 receptor protein; at the endthe VRl+-oocytes were tested by double electode voltage clamp.When we stimulated the oocytes with capsaicin (10-7M) , the cells were in response .to the stimuli; and with capsazepine (KT M) (specific inhibitor of VR1)+capsaicin (10-7 M), the cells had no response (n=3). So the capsaicin receptor was confirmed to express in oocytes. After we stimulated the cells with a series concentration (10-4M and 10-3M)of formaldehyde (n=3), the formaldehyde was able to activate the capsaicin receptor.
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