Morphine-pathway block in top1 poppies

Millgate, Anthony G; Pogson, Barry J.; Wilson, Iain W.; Kutchan, Toni M.; Zenk, Meinhart H.; Gerlach, W. L.; Fist, A. J.; Larkin, P. J.

doi:10.1038/431413a

Cited by 103 publications

(57 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An alternative is the demethylation of thebaine initially in the 3 position to yield oripavine, with further 6-O-demethylation to morphinone, which is enzymatically reduced to morphine. It is remarkable that chemotypes of the poppy plant exist in which either route is dominant or even exclusive (32). We have demonstrated here that [7D]-thebaine is formed by mice after injection (i.p.)…”

Section: Resultsmentioning

confidence: 78%

Urinary excretion of morphine and biosynthetic precursors in mice

Grobe

Lamshöft

Orth³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

It has been firmly established that humans excrete a small but steady amount of the isoquinoline alkaloid morphine in their urine. It is unclear whether it is of dietary or endogenous origin. There is no doubt that a simple isoquinoline alkaloid, tetrahydropapaveroline (THP), is found in human and rodent brain as well as in human urine. This suggests a potential biogenetic relationship between both alkaloids. Unlabeled THP or [1;3; ]-THP was injected intraperitoneally into mice and the urine was analyzed. This potential precursor was extensively metabolized (96%). Among the metabolites found was the phenol-coupled product salutaridine, the known morphine precursor in the opium poppy plant. Synthetic [7D]-salutaridinol, the biosynthetic reduction product of salutaridine, injected intraperitoneally into live animals led to the formation of [7D]-thebaine, which was excreted in urine. [N-CD 3 ]-thebaine was also administered and yielded [N-CD 3 ]-morphine and the congeners [N-CD 3 ]-codeine and [N-CD 3 ]-oripavine in urine. These results show for the first time that live animals have the biosynthetic capability to convert a normal constituent of rodents, THP, to morphine. Morphine and its precursors are normally not found in tissues or organs, presumably due to metabolic breakdown. Hence, only that portion of the isoquinoline alkaloids excreted in urine unmetabolized can be detected. Analysis of urine by high resolution-mass spectrometry proved to be a powerful method for tracking endogenous morphine and its biosynthetic precursors.endogenous morphine | mammalian mophine | morphine biosynthesis | stable-isotope labeled morphine | high resolution-mass spectrometry T he occurrence of endogenous morphine in mammals has been a controversy over the past three decades. Goldstein (1-3) and Spector (4-7) and their associates pioneered the assumption that morphine occurs in mammals and plays an unknown role. Other groups claimed that the morphine found in rodents is of dietary origin (8, 9). Clear answers concerning the presence of morphine in animals have been obscured by inadequate experimentation and possible laboratory contamination with morphine. Only recently, several reports appeared using sterile human cell cultures and isolated organs, which added to a body of evidence that morphine indeed occurs in mammals and human cell cultures (10-12). To substantiate these findings, we made use of the fact that morphine is excreted in urine of humans (13-15) and rats (7). The presence of morphine in urine has been unequivocally demonstrated by mass spectrometry (15), but the origin of the excreted morphine has not yet been clarified. If these trace amounts of morphine in urine are formed de novo (and are not from dietary intake), a biosynthetic apparatus should be present in mammals that catalyzes this multistep pathway.The goal of this investigation is to demonstrate the de novo formation of benzylisoquinoline alkaloids, mainly of the morphinan type, in live rodents. Our experimental strategy involves administration of stable-...

show abstract

Section: Resultsmentioning

confidence: 78%

Urinary excretion of morphine and biosynthetic precursors in mice

Grobe

Lamshöft

Orth³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

show abstract

“…1) and so are well-placed for comparative studies. P. somniferum is one of the oldest cultivated medicinal plants, and its continuing pharmaceutical importance as the source of a variety of morphinan alkaloids has made it one of the best-studied Papaver species (Chitty et al, 2006;Kapoor, 1995;Millgate et al, 2004;Zulak et al, 2007). Furthermore, functional genetic analyses can be rapidly carried out in P. somniferum using virus-induced gene silencing (Hileman et al, 2005).…”

Section: Functional Analyses Of Genetic Pathways Controlling Petal Spmentioning

confidence: 99%

Functional analyses of genetic pathways controlling petal specification in poppy

et al. 2007

View full text Add to dashboard Cite

MADS-box genes are crucial regulators of floral development, yet how their functions have evolved to control different aspects of floral patterning is unclear. To understand the extent to which MADS-box gene functions are conserved or have diversified in different angiosperm lineages, we have exploited the capability for functional analyses in a new model system, Papaver somniferum (opium poppy). P. somniferum is a member of the order Ranunculales, and so represents a clade that is evolutionarily distant from those containing traditional model systems such as Arabidopsis, Petunia, maize or rice. We have identified and characterized the roles of several candidate MADS-box genes in petal specification in poppy. In Arabidopsis, the APETALA3 (AP3) MADS-box gene is required for both petal and stamen identity specification. By contrast, we show that the AP3 lineage has undergone gene duplication and subfunctionalization in poppy, with one gene copy required for petal development and the other responsible for stamen development. These differences in gene function are due to differences both in expression patterns and cofactor interactions. Furthermore, the genetic hierarchy controlling petal development in poppy has diverged as compared with that of Arabidopsis. As these are the first functional analyses of AP3 genes in this evolutionarily divergent clade, our results provide new information on the similarities and differences in petal developmental programs across angiosperms. Based on these observations, we discuss a model for how the petal developmental program has evolved.

show abstract

“…Like T, top1 accumulates thebaine and oripavine but not morphine. Millgate et al (2004) suggested that a gene encoding a single demethylase, or one regulating its activity, might be affected in the top1 mutant. This phenotype might also result from a structural or transport component that prevents thebaine and oripavine from trafficking to the subcellular compartment where O-demethylation occurs.…”

Section: Accumulation Of Tyramine In Low-alkaloid Poppy Suggests Altementioning

confidence: 99%

“…This phenotype might also result from a structural or transport component that prevents thebaine and oripavine from trafficking to the subcellular compartment where O-demethylation occurs. As part of their characterization of top1, Millgate et al (2004) used a microarray-based approach to examine global changes in gene expression relative to the high-morphine parent. Although several genes were expressed at lower levels in top1, including an ATP-dependent membrane transporter and three putative enzyme-encoding genes, the differential accumulation of transcripts encoding an oxidative, demethylating enzyme that uses thebaine or oripavine was not detected.…”

Section: Accumulation Of Tyramine In Low-alkaloid Poppy Suggests Altementioning

confidence: 99%

See 1 more Smart Citation

Quantitative 1H Nuclear Magnetic Resonance Metabolite Profiling as a Functional Genomics Platform to Investigate Alkaloid Biosynthesis in Opium Poppy

et al. 2008

View full text Add to dashboard Cite

Opium poppy (Papaver somniferum) produces a diverse array of bioactive benzylisoquinoline alkaloids and has emerged as a versatile model system to study plant alkaloid metabolism. The plant is widely cultivated as the only commercial source of the narcotic analgesics morphine and codeine. Variations in plant secondary metabolism as a result of genetic diversity are often associated with perturbations in other metabolic pathways. As part of a functional genomics platform, we used 1 H nuclear magnetic resonance (NMR) metabolite profiling for the analysis of primary and secondary metabolism in opium poppy. Aqueous and chloroform extracts of six different opium poppy cultivars were subjected to chemometric analysis. Principle component analysis of the 1 H NMR spectra for latex extracts clearly distinguished two varieties, including a low-alkaloid variety and a high-thebaine, low-morphine cultivar. Distinction was also made between pharmaceutical-grade opium poppy cultivars and a condiment variety. Such phenotypic differences were not observed in root extracts. Loading plots confirmed that morphinan alkaloids contributed predominantly to the variance in latex extracts. Quantification of 34 root and 21 latex metabolites, performed using Chenomx NMR Suite version 4.6, showed major differences in the accumulation of specific alkaloids in the latex of the low-alkaloid and high-thebaine, low-morphine varieties. Relatively few differences were found in the levels of other metabolites, indicating that the variation was specific for alkaloid metabolism. Exceptions in the lowalkaloid cultivar included an increased accumulation of the alkaloid precursor tyramine and reduced levels of sucrose, some amino acids, and malate. Real-time polymerase chain reaction analysis of 42 genes involved in primary and secondary metabolism showed differential gene expression mainly associated with alkaloid biosynthesis. Reduced alkaloid levels in the condiment variety were associated with the reduced abundance of transcripts encoding several alkaloid biosynthetic enzymes.

show abstract

Morphine-pathway block in top1 poppies

Cited by 103 publications

References 6 publications

Urinary excretion of morphine and biosynthetic precursors in mice

Urinary excretion of morphine and biosynthetic precursors in mice

Functional analyses of genetic pathways controlling petal specification in poppy

Quantitative 1H Nuclear Magnetic Resonance Metabolite Profiling as a Functional Genomics Platform to Investigate Alkaloid Biosynthesis in Opium Poppy

Contact Info

Product

Resources

About