Journal of Neuroscience, Vol 7, 2338-2343, Copyright © 1987 by Society for Neuroscience
Excitable properties of olfactory receptor neurons
B Hedlund, LM Masukawa and GM Shepherd
Action potential-generating properties of olfactory receptor neurons in the
olfactory epithelium of the salamander, Ambystoma tigrinum, were studied in
control animals, and 2 and 4 weeks after olfactory nerve transection. The
threshold for impulse generation in response to injected current was
extremely low (74 +/- 46 pA). In addition, the discharge frequencies of the
receptor neurons were exquisitely sensitive to small increments of injected
current. These high sensitivities may be characteristic of small neurons
and stand in contrast to the much lower sensitivities reported for large
neurons. The high sensitivity has important implications for the
input-output functions of this cell. After nerve transection, both the
threshold and the frequency sensitivity decreased. These changes appear to
be associated with increased potassium conductance, suggested by prominent
membrane rectification and reduced amplitudes of later membrane action
potentials in the spike trains. The olfactory receptor neuron appears to be
a favorable model for exploring these properties.