THE EFFECT OF TEMPERATURE CHANGE ON THE 

 RESPONSE OF TASTE RECEPTORS 



Masayasu Sato 



Department of Physiology, Kumamoto University Medical School, 

 Kumamoto, Japan 



Previous experimental results on the effect of temperature change on taste 

 sensation of human subjects are not consistent. It is reported Weber (1847) 

 found that the sensitiveness of taste sensation was greatest when the excit- 

 ing substance was at the temperature of body (Moncrieff, 1951). How- 

 ever, the work by Hahn (1936) shows that within a temperature range of 

 17-42°C the sensitivity to sugar increases with an optimum at 37°C, salt 

 and quinine sensitivity decreases and acid is unaffected by temperature. 



Recent studies on the effect of temperature on the response of taste 

 receptors of mammals using electrophysiological methods have not 

 yielded significant results. Abbott (1953) found an optimal response at 

 22'C in rats, Beidler (1954) reported no change in response magnitude of 

 taste receptors in rats for 0.5 m sodium chloride at temperatures of 20°, 

 25 and 30 C, and Fishman (1957) observed in rats and hamsters smaller 

 response to 0.5-1.0 m salts at 5 C than normally obtained at 25 C. There- 

 fore no systematic investigation on the effect of temperature change on the 

 response from taste receptors covering wide temperature range and various 

 kinds of taste stimuli have yet been accomplished. 



Therefore Dr. Nagaki, Mr. Yamashita and i carried out experiments 

 in which response of taste receptors was measured by changing tempera- 

 ture of various kinds of taste solutions. We have adopted two kinds of 

 approaches to this problem. First, the integrated response of the chorda 

 tympani nerve to stimulation of the tongue by various kinds of solutions 

 at varying temperatures was recorded ; second, impulse discharge in a 

 single chorda tympani nerve fibre due to stimulation of the tongue was 

 recorded and analyzed. In order to stimulate a constant area of the tongue, 

 the anterior two-thirds of the tongue were placed in a flow chamber and 

 100 ml of the solution were flowed over the tongue for 10 to 15 sec, and 

 subsequently the tongue was rinsed with Ringer's solution. 



Temperature of the solution and change in the surface temperature of the 

 tongue were recorded with a thermistor. Temperature of the tongue surface 

 of the anaesthetized cat was generally about 30X and a fairly constant 



151 



