Question

Explain how atropine, an anticholinergic, acts as an antagonist at cholinergic receptors

Answer 1

Atropine is an cholinergic antagonist so it literally blocks the binding site for ACh (acetylcholine) and prevents the natural muscarinic (think resting and digesting) responses of the body. It helps increase bronchial airways (for asthma) and used to be used in surgery when ether was used because it would prevent secretions from choking the patients. It also helps if you have overdosed on poisonous mushrooms. If you overdose on it-there is a saying of "dry as a bone, red as a beet, blind as a bat, mad as a hatter." Think of Alice in Wonderland for the mad hatter. What this means is the body cannot make tears, sweat, or spit. There tends to be constipation and you cannot urinate or vomit. Since you can't sweat, the body gets really warm and red. The pupils become really large and the lens cannot focus so you can't see right. It also blocks receptors in the brain and can cause hallucinations, confusion, and delirium