= Physostigmine
<Physostigmine> is a carbamate <alkaloid> that inhibits <acetylcholinesterase>. Normally this <enzyme> hydrolyses <acetylcholine>; inhibition prolongs the availability of <acetylcholine> at cholinergic signalling sites. <Physostigmine> is therefore an indirect enhancer of cholinergic signalling, rather than simply a substitute <ligand> for every acetylcholine <receptor>. <PubChem Compound database by National Center for Biotechnology Information>[Physostigmine, CID 5983, Pharmacology and Biochemistry: reversible cholinesterase inhibition]{ref}
A mechanistic distinction matters: increasing transmitter persistence can affect both muscarinic and nicotinic signalling wherever transmitter release and susceptible <receptors> occur. The outcome therefore depends on location, <receptor> type and baseline activity. This example separates an enzyme-directed <drug> action from the eventual physiological response, without assuming one universal effect in every <tissue>.
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