Transmembrane currents in frog olfactory cilia.

We have measured transmembrane currents in intact single cilia from frog olfactory receptor neurons. A single cilium on a neuron was sucked into a patch pipette, and a high-resistance seal was formed near the base of the cilium. Action potentials could be induced by applying suction or a voltage ramp to the ciliary membrane. A transient current was seen in some cells on stimulation with odorants. After excision from the cell, most of the cilia showed increased conductance in a bath containing cAMP, indicating that the cytoplasmic face of the ciliary membrane was accessible to the bath. The estimated resistance of a single cilium was surprisingly low.