Odontoblasts play an important role in the transduction of the sensory signals underlying dentinal pain. Transmembrane voltage-independent Ca
2+ influx in odontoblasts has been well described. Voltage-dependent Ca
2+ influx has also been reported, but its biophysical properties remain unclear. The aim of the present study was to investigate the desensitizing effect of voltage-dependent Ca
2+ influx in rat odontoblasts by measuring depolarization-induced intracellular free Ca
2+ concentrations ([Ca
2+ ]
i ). Odontoblasts on dental pulp slices from newborn rats were acutely isolated and [Ca
2+ ]
i measured by using fura-2 fluorescence. Repeated application of extracellular high-K
+ solution (50 mM), which induces membrane depolarization-elicited repeated and transient increases in [Ca
2+ ]
i in the presence of extracellular Ca
2+. Increases in depolarization-induced [Ca
2+ ]
i showed no significant desensitizing effect (p >0.05; Friedman test). These results suggest that odontoblasts express a voltage-dependent Ca
2+ influx pathway with no desensitizing properties.
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