(+)-Morphine also known as dextro-morphine is the "unnatural" enantiomer of the opioid drug (−)-morphine. Unlike "natural" levo-morphine, unnatural dextro-morphine is not present in Papaver somniferum and is the product of laboratory synthesis.
-Morphine.svg) | |
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| Formula | C17H19NO3 |
| Molar mass | 285.343 g·mol−1 |
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In contrast to natural morphine, the unnatural enantiomer has no affinity or efficacy for the mu opioid receptor and therefore has no analgesic effects. To the contrary, in rats, (+)-morphine acts as an antianalgesic and is approximately 71,000 times more potent as an antianalgesic than (−)-morphine is as an analgesic.[1] (+)-Morphine derives its antianalgesic effects by being a selective-agonist of the Toll-like receptor 4 (TLR4), which due to not binding to opioid receptors allows it to effectively reverse the analgesic properties of (−)-morphine. TLR4 is involved in immune system responses, and activation of TLR4 induces glial activation and release of inflammatory mediators such as TNF-α and Interleukin-1.[2][3]
See also
editReferences
edit- ^ Wu HE, Thompson J, Sun HS, Terashvili M, Tseng LF (September 2005). "Antianalgesia: stereoselective action of dextro-morphine over levo-morphine on glia in the mouse spinal cord". The Journal of Pharmacology and Experimental Therapeutics. 314 (3): 1101–1108. doi:10.1124/jpet.105.087130. PMID 15901793. S2CID 7190985.
- ^ Hutchinson MR, Zhang Y, Shridhar M, Evans JH, Buchanan MM, Zhao TX, et al. (January 2010). "Evidence that opioids may have toll-like receptor 4 and MD-2 effects". Brain, Behavior, and Immunity. 24 (1): 83–95. doi:10.1016/j.bbi.2009.08.004. PMC 2788078. PMID 19679181.
- ^ Hutchinson MR, Lewis SS, Coats BD, Rezvani N, Zhang Y, Wieseler JL, et al. (May 2010). "Possible involvement of toll-like receptor 4/myeloid differentiation factor-2 activity of opioid inactive isomers causes spinal proinflammation and related behavioral consequences". Neuroscience. 167 (3): 880–893. doi:10.1016/j.neuroscience.2010.02.011. PMC 2854318. PMID 20178837.