You have seen that when finding the response of a tissue to agonists the length of time the tissue is exposed to an agonist has to stay the same throughout the experiment.
When using antagonists, the tissue has to equilibrate and the time allowed for equilibration has to be the same throughout the experiment.
Time Allowed for Equilibration Must Remain Constant
As for the exposure time, the equilibration time will depend on such factors as what tissue is used and what drugs are used.
In this simulation, the time for the guinea pig ileum to equilibrate with an antagonist is set at five minutes.