Acetylcholine chloride, carbachol – the so-called direct cholinomimetics have a stimulating effect on cholinergic transmission. They directly interact with m- and n-cholinergic receptors. However, anticholinesterase agents (physostigmine, galantamine, neostigmine methyl sulfate, pyridostigmine bromide, aminostigmine, rivastigmine, ipidacrine, etc.) are more often used for this purpose. They inhibit cholinesterase – an enzyme that destroys endogenous acetylcholine, cause the accumulation of acetylcholine in the endings of cholinergic nerves and enhance its effect on organs and tissues. Therefore, the effects of anticholinesterase substances are largely similar to those of acetylcholine.
Depending on the chemical structure and physicochemical properties, different drugs in this group differ from each other. Tertiary amines (physostigmine, galantamine, etc.) penetrate biological membranes, including the BBB, and have an activating effect on the central nervous system. For quaternary ammonium derivatives (neostigmine methyl sulfate, pyridostigmine bromide, ambenonium chloride, etc.), the BBB is difficult to pass, so they mainly affect the peripheral cholinergic systems. There are substances (armin, paraoxon) that irreversibly (covalently) bind cholinesterase. They are highly active, but also very toxic, which limits their clinical use.
Below is a list of m-, n-cholinomimetics, incl. anticholinesterase agents:
- Aminostigminum (Aminostigminum)
- Pyridostigmine bromide
- Neostigmini methylsulfas
- Dystigmine bromide