- Endogenous analgesics: do humans have the ability to synth...
Endogenous analgesics: do humans have the ability to synthesise morphine?
The alkaloid compound morphine is one of the strongest known
opioid analgesic compounds and has a wide range of therapeutic
applications (Yaksh 1997). Morphine was first isolated from the
opium poppy Papaver somniferum, where it can be found in high
levels (Shukla et al 2006). Trace amounts of morphine have been
found in human tissues and fluids, where it was believed to be
dietary in origin, coming from the ingestion of morphine-containing
plant substances. Recent findings have disputed this fact and have
raised questions over whether the traces of morphine found in
humans and animals are dietary or endogenously synthesised.
Biosynthetic experiments on human neuroblastoma cells have shown
that carcinoma cells have the ability to synthesise morphine
(Poeaknapo et al 2005). If this is translated to normal human cells
then this would provide further evidence for the ability of human
cells to synthesise morphine. Furthermore, the precursors for
endogenous morphine synthesis in human cell lines have also been
identified as oxygen, tyramine, reticulin and thebane. It seems
that humans' cells have the required substrates to produce
In summary, the evidence shows that morphine is produced
endogenously in humans. There have been several suggestions
of its function or benefit to humans although knowledge in this
area is not currently conclusive. Further studies will be
required to conclusively show the physiological function of
endogenous morphine in human beings.