Coding properties at steady-state of the receptor potential were analyzed in a biophysical model of an olfactory neuron with and without taking into account the auxiliary cells that surround it. It was found that the neuron model without auxiliary cells has generally a higher sensitivity and a narrower dynamic range. The dynamic range is wide when the input resistance of passive dendrite, soma and axon is small and the sensory dendrite is unbranched, whereas the sensitivity is high in the opposite conditions. Both coding properties are large for a long enough dendrite.