Background: Ultraviolet light irradiation has been shown to suppress immunological reactions of irradiated individuals, however, less attention has been paid to the effects on neurogenic inflammation.
Objective: We have investigated the effect of ultraviolet light B (UVB) irradiation on substance P (SP)-induced histamine release from rat mast cells.
Methods: Rat peritoneal mast cells were treated with UVB irradiation and challenged by SP. Histamine release from the cells and intracellular calcium concentrations ([Ca2+]i) in the cells were measured.
Results: UVB irradiation at doses used in the present study did not induce histamine release from mast cells. UVB irradiation at doses from 25 to 200 mJ/cm2 inhibited 10(-5) mol/L SP-induced histamine release in a dose-dependent manner. On the other hand, SP-induced increase of [Ca2+]i was inhibited by UVB irradiation only at doses of 100 and 200 mJ/cm2.
Conclusion: These data suggest that UVB irradiation inhibits histamine release from SP-activated rat peritoneal mast cells partially through the suppression of an increase in [Ca2+]i.