S. Firestein et al., THE RELATION BETWEEN STIMULUS AND RESPONSE IN OLFACTORY RECEPTOR-CELLS OF THE TIGER SALAMANDER, Journal of physiology, 468, 1993, pp. 1-10
1. Olfactory receptor cells were isolated from the adult tiger salaman
der Ambystoma tigrinum and the current in response to odorant stimuli
was measured with the whole-cell voltage-clamp technique while odorant
s at known concentrations were rapidly applied for controlled exposure
times. 2. Three odorants, cineole, isoamyl acetate and acetophenone,
were first applied at 5 x 10(-4) m. Out of forty-nine cells tested, 53
% responded to one odorant only, 22 % to two odorants and 25 % to all
three odorants. 3. The amplitude of the current in response to a give
n odorant concentration was found to be dependent on the duration of t
he odorant stimulus and reached a saturating peak value at 1.2 s of st
imulus duration. 4. The current measured at the peak of the response f
or odorant steps of 1.2 s as a function of odorant concentration was w
ell described by the Hill equation for the three odorants with Hill co
efficients higher than 1 and K 1/2 (odorant concentration needed to ac
tivate half the maximal current) ranging from 3 x 10(-6) to 9 x 10(-5)
m. 5. It is concluded that olfactory receptor cells are broadly tuned
and have a low apparent affinity for odorants, integrate stimulus inf
ormation over time, and have a narrow dynamic range.