Atropine classification

Muscarine is a natural alkaloid that is found in a number of wild mushrooms. Despite the fact that muscarine does not have any therapeutic value, it is of interest because of its expressed toxic properties, which made it one of the first systematically studied cholinomimetic substances. This compound was an underlying classification of cholinergic muscarinic receptors. The action of muscarine is similar to that of acetylcholine on peripheral autonomic effector organs, and atropine is an antagonist to it. Unlike acetylcholine, muscarine does not act on nicotinic receptors. 

It is usual to classify as psychotomimetic, substances which produce predominantly psychotic effects in low concentrations. Many other drugs (cocaine, amphetamine and atropine, for instance) have psychotomimetic side effects or are effective psychotomimetics in relatively high doses. They are, therefore, not usually grouped with the psychotomimetic drugs, but since the criteria of psychotomimetic action are rather imprecise, differences of opinion do arise concerning the classification of some of the less active substances. The names and formulae of some of the compounds generally recognized as psychotomimetic are set out in Table 5.6. 

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