BACKGROUND: Toluene diisocyanate (TDI), a low molecular weight compound,is commonly known as a factor causing asthma in chemical industry workers. The present study investigateda possible effect of TDI on ion transport using electrophysiological methods aimed at assessment of ioncurrents occurring in epithelial tissues. MATERIAL/METHODS: The experiments were carried out on 119 fragmentsof isolated frog skin, sampled from 59 specimens of hybrid frog Rana esculenta L. The procedures employedinvolved transepithelial electrical potential (PD in mV) measurement with an Ussing apparatus, modifiedto enable mechanical stimulation of organs and defined pharmacological actions. Incubation was carriedout using Ringer solution and Ringer solution with amiloride and bumetanide. Direct actions of toluenediisocyanate (TDI) were assessed at the time of administering this substance to the Ussing chamber witha peristaltic pump. RESULTS: Based on the model of frog skin tested with Ussing apparatus, administrationof TDI to the fluid stimulating preparations incubated with Ringer solution (RH) and with amiloride (AMI)was demonstrated to cause a hyperpolarization increase after mechanical stimulation. TDI action on isolatedfrog skin inflicted a change in response to mechanical stimulation, leading to a depolarization. Thereaction magnitude of frog skin incubated with bumetanide (BUME) did not change due to TDI. CONCLUSIONS:TDI influences processes of sodium ion transport in the isolated frog skin model, depending on mechanicalstimulation. This indicates that TDI effect on ion transport in epithelial cells depends on C fibresand tachykinins released from their endings.

Keywords: Amiloride, Electrophysiology, Ion Transport, Ions, Isotonic Solutions, Ranidae, Skin, Tachykinins, Toluene 2,4-Diisocyanate