Abstract
The suppressive effects of low-power laser on excitations evoked by bradykinin in cultured murine dorsal root ganglion neurons associated with C-fibers were studied by measuring cytosolic calcium ion concentrations with confocal laser scanning microscopy. Elevation of the cytosolic calcium ion concentration and calcium oscillations were observed by the stimulation of neurons with bradykinin in a calcium-rich external solution. Any typical calcium oscillation was not observed in a calcium-free solution. The elevation of the calcium ion concentration elicited by bradykinin was suppressed by the irradiation with a Ga-Al-As diode laser (wave length: 830 nm, output power: 16.2 mW, irradiation energy: 49 J/cm2). The suppression was reversible. The laser irradiation does not block the binding of bradykinin to B2 receptor but may interfere with cell membrane components by which action potentials and calcium ion flux might be brought out.
