58 



DON TUCKER 



caused by an approach to equality of odorant chemical potential in the 

 medium of the receptor sites with that in the gaseous medium entering the 

 naris, which is known. Since this discussion applies to the phasic olfactory 

 response, the odorant thermo-dynamic activity specified at the receptors is 



OLFACTORY NERVE RESPONSE 



CURVE PARAMETERS ARE ODOR 



DON :entrat 



AMYL ACETATE 



FLOW RATE 



IONS 



BENZYL AMINE 



FLOW RATE 



?OUGH THE NOSE 



Fig. 13. Phasic olfactory responses graphed as a function of nasal flow rate for 

 two odorants. Unit concentration is air saturated at 20°C. 



that which is attained in a time of the order of a characteristic time inferred 

 for initiation of the response. It may be possible, then, to relate the res- 

 ponse of the receptor to the stimulus at the level of the receptor. Indeed, 

 olfactory responses to amyl acetate taken in the range of flow rate for 

 plateauing of the response were found to be quantitatively similar in dif- 

 ferent preparations. Response data as a function of concentration were 

 fitted with Beidler's (1961) taste equation for two different sets of inde- 

 pendent sites. The algebraic form of the equation is 

 . _ R, K, [A] R, K, [A-\ 

 l+K^iA] 1 + K^ lA] 

 and the transcendental form for the semilogarithmic plot is 



R, 



2 



where r,- is the response (r = Sr,) 



Ri is the maximal value of response 

 Ki is the equilibrium constant 

 [A] is the concentration of amyl acetate 

 / is the site index. 



^1 



r = — 



2 



(1 + tanh \\\\K^ [A\ 



(1 



tanhi In K^ [A\, 



