Dihydro-/3-erythroidine nicotinic receptor antagonist

Drugs that block the nicotinic receptors on autonomic ganglia, such as hexamethonium, probably do so by actually blocking the Na+ ion channel rather than the receptor. Generally these receptors appear to resemble the central ones more than those at the neuromuscular junction and dihydro-jS-erythroidine is one drug that it is an effective antagonist in both ganglia and the CNS. 

Erysodine (6) has been found to be a competitive, reversible antagonist of nicotine-induced dopamine release. It is equipotent with dihydro-/ -erythroidine (226) and may be a useful tool to characterize neuronal nicotinic acetylcholine receptors (727). 

From all the pure alkaloids tested a- and yS-erythroidine exhibit the highest activity (727). They have been assumed to be the principles responsible for the hypnotic activity of the extracts of the flowers of E. americana 19). /)-Eyrthroidine (225) and its more potent 2,7-dihydro-derivative 226 have been used as muscle relaxant in numerous clinical applications 114, 120). This activity is attributed to an antagonistic action of dihydro-/3-erythroidine to nicotinic acetylcholine receptors, which is now well known and is frequently used in the experimental pharmacology (79, 725, 726). 

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