Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
Abstract:
A theoretical model which can account for both the dynamic and steady responses is proposed based on the occupation theory. The reaction scheme used is; where p and C stand for the fraction of (SA)active to the total number of receptor sites and stimulus concentration, respectively, and αi, and ωi (i = 1, 2) are numerical parameters depending on the rate constants and on C. The steady response is expressed as the third term in the above equation, which indicates that the response accords with the Beidler taste equation. Mathematical analysis of the above scheme shows that the dynamic response appears when k1C > k?2, and the calculated results for the dynamic response agree approximately with the Hill equation. The Hill coefficient lays within 1·00 and 0·79 and reaches unity with increasing , which implies that the dynamic response under this condition satisfies the Beidler taste equation. For the case of gradual application of stimuli, i.e. the experimental condition, the time course of p is simulated with use of an analogue computer rather than with a numerical solution to the above equation. The results indicate that the dynamic response diminishes with decreasing the application speed of stimulus solution. The present theory accounts consistently for various experimental data observed in the chemoreceptor systems.
where p and C stand for the fraction of (SA)active to the total number of receptor sites and stimulus concentration, respectively, and αi, and ωi (i = 1, 2) are numerical parameters depending on the rate constants and on C. The steady response is expressed as the third term in the above equation, which indicates that the response accords with the Beidler taste equation. Mathematical analysis of the above scheme shows that the dynamic response appears when k1C > k?2, and the calculated results for the dynamic response agree approximately with the Hill equation. The Hill coefficient lays within 1·00 and 0·79 and reaches unity with increasing , which implies that the dynamic response under this condition satisfies the Beidler taste equation. For the case of gradual application of stimuli, i.e. the experimental condition, the time course of p is simulated with use of an analogue computer rather than with a numerical solution to the above equation. The results indicate that the dynamic response diminishes with decreasing the application speed of stimulus solution. The present theory accounts consistently for various experimental data observed in the chemoreceptor systems.