EFFECT OF SUBSTANCE-P ON THE SHORT-CIRCUIT CURRENT OF RAT NASAL MUCOSAL EPITHELIUM

Rats were sensitized by intranasal application of toluene diisocyanate as a nasal allergy model. By means of the Ussing chamber technique, r at nasal epithelial short-circuit current (Isc) was measured. Enhanced Isc of the rat nasal mucosa resulted from stimulation of substance P (SP) in a dose-dependent manner that could be inhibited by pretreatmen t with NK1 receptor antagonist CP-96345, the H1 receptor antagonist py rilamine, the H2 receptor antagonist ranitidine, and the neurotoxin te trodotoxin, respectively, to different extents. The results indicate t hat SP is able to cause ion secretion of the nasal mucosal epithelium, perhaps by activating mast cells to release histamine. These data sug gest that mast cells and sensory nerves participate in the regulation of SP-induced ion secretion during nasal allergy.