Infusing drug concentration- and speed-response curves

A semi-mechanized method for the determination of infusing drug concentration- and speed-response curves in isolated rabbit aortic strips, rat gastric fundi, guinea pig vas deferenses and rat anococcygeal muscles was developed. The natures of the infusing drug concentration-response curves and relation between the infusing effect and releasing effect were analysed. Our experimental results showed the agonism and antagonism of agonists coexisted, and so-called “pure” agonists did not exist. A revised definition for agonists and antagonists was put forward. The results also showed that the drug effects not only depended on the terminal concentration in organ bath, but also the speed of drug infusion. For lack of the new concept of speed-response relationship, both occupation theory and rate theory based only on the drug concentration-response relationship can hardly interpret the formations of Epeak and Equilibrum observed in our experiments. Summing up the useful views of both theories, the authors proposed an alternative theory.