Direct Cholinergic Agonists Vs Indirect Acting Cholinergic Agonists

Question 1

What are Direct cholinergic agonists?

Answer 1

Direct Cholinergic Agonists: These drugs directly stimulate cholinergic receptors by binding to them, mimicking the action of acetylcholine (ACh) itself. They activate the muscarinic and, in some cases, nicotinic receptors, leading to physiological responses similar to ACh. Examples include drugs like bethanechol and pilocarpine.
- Direct Agonists: Act directly on receptors.

Question 2

What are indirect acting cholinergic agonists?

Answer 2

Indirect-Acting Cholinergic Agonists: Instead of binding to receptors, these drugs increase the levels of acetylcholine by inhibiting the enzyme acetylcholinesterase, which normally breaks down ACh. By preventing ACh degradation, indirect agonists allow ACh to accumulate and prolong its action at cholinergic receptors. Examples include neostigmine and physostigmine.
-Indirect Agonists: Inhibit acetylcholinesterase, increasing ACh concentration and action indirectly.