MR-2034

MR-2034
Clinical data
Other namesMR2034; Mr-2034; (–)-MR-2033; (–)-MR2033
Drug classκ-Opioid receptor agonist; Hallucinogen
ATC code
  • None
Identifiers
  • (1R,9R)-1,13-dimethyl-10-[[(2R)-oxolan-2-yl]methyl]-10-azatricyclo[7.3.1.02,7]trideca-2(7),3,5-trien-4-ol
CAS Number
PubChem CID
ChemSpider
CompTox Dashboard (EPA)
Chemical and physical data
FormulaC19H27NO2
Molar mass301.430 g·mol−1
3D model (JSmol)
  • CC1[C@H]2CC3=C([C@@]1(CCN2C[C@H]4CCCO4)C)C=C(C=C3)O
  • InChI=1S/C19H27NO2/c1-13-18-10-14-5-6-15(21)11-17(14)19(13,2)7-8-20(18)12-16-4-3-9-22-16/h5-6,11,13,16,18,21H,3-4,7-10,12H2,1-2H3/t13?,16-,18-,19-/m1/s1
  • Key:NLKLXMMOJZHSCB-SENCRUMESA-N

MR-2034, or Mr-2034, also known as (–)-MR-2033, is a selective κ-opioid receptor (KOR) agonist of the benzomorphan family.[1][2] Unlike other benzomorphan KOR agonists like cyclazocine and alazocine, MR-2034 does not also act on sigma receptors.[2] In addition to the KOR, it has affinity for the μ-opioid receptor (MOR), but does not activate this receptor.[2] The drug produces dose-dependent hallucinogenic and dysphoric effects in humans, as well as other effects such as dizziness, anxiety, and sedation.[3][2] These effects can be blocked by the non-selective opioid receptor antagonist naloxone.[2] The preceding findings led to the conclusion that the hallucinogenic and dysphoric effects of benzomorphans are mediated by the KOR rather than by sigma receptors.[2] MR-2034 was first described in the scientific literature by 1975[4][5] and its hallucinogenic effects in humans were described in 1986.[2]

References

  1. ^ Coupar JM, Quinn MJ (May 1988). "The effects of the selective kappa-opioid agonist MR 2034 on the guinea-pig ileum". The Journal of Pharmacy and Pharmacology. 40 (5): 378–380. doi:10.1111/j.2042-7158.1988.tb05274.x. PMID 2899640.
  2. ^ a b c d e f g Pfeiffer A, Brantl V, Herz A, Emrich HM (August 1986). "Psychotomimesis mediated by kappa opiate receptors". Science. 233 (4765): 774–776. doi:10.1126/science.3016896. PMID 3016896.
  3. ^ Farahbakhsh ZZ, Siciliano CA (January 2026). "Kappa opioid receptor control of motivated behavior revisited". Neuropsychopharmacology. 51 (2): 383–398. doi:10.1038/s41386-025-02226-9. PMC 12708679. PMID 41083597.
  4. ^ Kosterlitz HW, Hughes J (July 1975). "Some thoughts on the significance of enkephalin, the endogenous ligand". Life Sciences. 17 (1): 91–96. doi:10.1016/0024-3205(75)90243-x. PMID 806763.
  5. ^ Hutchinson M, Kosterlitz HW, Leslie FM, Waterfield AA (December 1975). "Assessment in the guinea-pig ileum and mouse vas deferens of benzomorphans which have strong antinociceptive activity but do not substitute for morphine in the dependent monkey". British Journal of Pharmacology. 55 (4): 541–546. doi:10.1111/j.1476-5381.1975.tb07430.x. PMC 1666732. PMID 2359.