Guinea Pig Agonist

Background and Aims: An agonist produces a physiological response upon binding to a receptor while an antagonist inhibits agonist-mediated responses. It is reported that muscarinic acetylcholine receptors, located on the ileum of the small intestine, initiate contractile activity when an agonist (acetylcholine) is present. The purpose of this study was to examine the effects of a competitive antagonist (atropine) on the muscarinic acetylcholine receptors.

Methods: The isolated guinea pig ileum was suspended in an organ bath containing a physiological salt solution (Krebs Solution) in which the temperature was maintained at 37C and was continuously gassed with 5% carbon dioxide in oxygen. The tension changes were recorded using an isometric