Spiking properties of olfactory receptor cells in the slice preparation.

The whole-cell, patch clamp [corrected] method was applied to olfactory receptor cells in slice preparations made from bullfrog olfactory epithelium. Under voltage-clamp conditions, olfactory receptor cells showed a transient inward current followed by a steady outward current in response to depolarizing voltage steps, as has been shown in the isolated preparation. The input resistance was 5.4 +/- 3.9 GOmega and capacitance 21.9 +/- 9.7 pF. Under current-clamp conditions, depolarization of cells by current injection induced action potentials. In 13 out of 20, spike generation was repetitive with a maximum frequency of 24 Hz. The frequency of the repetitive discharges increased as the injected current was increased. The relationship between the size of the injected current and firing frequency could be well fitted by the Michaelis-Menten equation, indicating that the spike generation site lacks the non-linear boosting system. The slice preparation developed here would provide a powerful tool to study the spike encoding system of the olfactory receptor cells.