In addition to dynorphin, a variety of natural alkaloids and synthetic ligands bind to the receptor.

These natural alkaloids have a much weaker effect than the amphetamine.

The first tranquillizer to be introduced to the medical world (in 1954) was reserpine, a natural alkaloid found in the dried roots of a shrub from India.

You see, caffeine is a natural alkaloid in more than 60 plants (including tea and coffee) and in plant derivatives known as "botanicals."

Furthermore drugs such as MDMA ("ecstasy", "molly") natural alkaloids like cocaine exert their effects in a large part by their interaction with MATs.

Particularly, yuehchukene differs from other natural bis-indole alkaloids because it does not seem to be derived from tryptophan.

The piperidine structural motif is present in numerous natural alkaloids.

Hydrastine is a natural alkaloid which was discovered in 1851 by Alfred P. Durand.

He was also awarded the prestigious Davy Medal in 1905 "for his researches in organic chemistry, especially in connection with the synthesis of natural alkaloids".

The pyrrolidine ring structure is present in numerous natural alkaloids such as nicotine and hygrine.