A piece of guinea pig ileum about 2 cm long is in an organ bath. The organ bath contains Tyrode's solution at 37oC. The solution is aerated continuously.
Agonist is then added using a 3 minute cycle:
0 minutes Add Agonist
0.5 minutes Wash Out Organ Bath
1.5 minutes Wash Out Organ Bath
3 minutes Add Agonist