Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Quantitative autoradiographic distribution of meptazinol-sensitive binding sites in rat brain


  1. 1.

    Meptazinol is an interesting opioid-producing naloxone-reversible analgesia with few cardiovascular and respiratory effects. Recent studies indicate that mu1 opioid receptors mediate meptazinol analgesia. Using a computerized autoradiographic subtraction technique, we have examined the regional distribution of meptazinol-sensitive [3H][d-Ala2,MePhe4,Gly(ol)5]enkephalin (DAGO) binding and compared this with the distribution of mu1 binding determined by competition with low [d-Ala2,d-Leu5]enkephalin (DADL) concentrations.

  2. 2.

    Meptazinol and DADL lowered [3H]DAGO to similar extents in most brain regions studied. The greatest levels of inhibition were observed in the periaqueductal gray, interpeduncular nucleus, thalamus, hypothalamus, and hippocampus. Low levels of inhibition were found in the temporal and frontal cortex. The correlation between the inhibition of [3H]DAGO binding by meptazinol and that by DADL was high (r = 0.83), consistent with the binding of meptazinol to mu1 sites.

This is a preview of subscription content, log in to check access.


  1. Bill, D., Cowlrick, I. S., Fox, J., Todd, M. H., Wood, M. D., and Wyllie, M. G. (1981). Does meptazinol bind to opiate receptors?Br. J. Pharmacol. 74866.

  2. Blurton, P. A., Broadhurst, A. M., Wood, M. D., and Wyllie, M. G. (1986). Is there a common high affinity opioid binding site in rat brain?J. Receptor Res. 685–93.

  3. Gintzler, A. R., and Pasternak, G. W. (1983). Multiple mu receptors: Evidence for mu2 sites in the guinea pig ileum.Neurosci. Lett. 3951–56.

  4. Goodman, R. R., and Pasternak, G. W. (1985). Visualization of mu1 opiate receptors in rat brain using a computerized autoradiographic technique.Proc. Natl. Acad. Sci. USA 826667–6671.

  5. Goodman, R. R., Adler, B. A., and Pasternak, G. W. (1985). Regional differences in mu1 binding of3H-DADL-enkephalin: Comparisons of thalamus and cortex.Neurosci Lett. 59155–158.

  6. Henry, J. A. (1985). Oral meptazinol-United Kingdom experience.Postgrad. Med. J. 6128–34.

  7. Ling, G. S. F., and Pasternak, G. W. (1983). Spinal and supraspinal analgesia in the mouse: The role of subpopulations of opioid binding sites.Brain Res. 71152–156.

  8. Ling, G. S. F., Spiegel, K., Nishimura, S., and Pasternak, G. W. (1983). Dissociation of morphine's analgesic and respirator depressant actions.Europ. J. Pharmacol. 86487–488.

  9. Ling, G. S. F., Macleod, J. M., Lee, S., Lockhart, S., and Pasternak, G. W. (1984). Separation of morphine analgesia from physical dependence.Science 226462–464.

  10. Ling, G. S. F., Spiegel, K., Lockhart, S. H., and Pasternak, G. W. (1985). Separation of opioid analgesia from respiratory depression: Evidence for different receptor mechanisms.J. Pharmacol Exp. Ther. 232149–155.

  11. Ling, G. S. F., Simantov, R., Clark, J. A., and Pasternak, G. W. (1986). Naloxonazine actions in vivo.Eur. J. Pharmacol. 12933–38.

  12. Lutz, R. A., Cruciana, R. A., Costa, T., Munson, P. J., and Rodbard, D. (1985a). Very high affinity opiate binding sites in rat brain: Demonstration by computer modeling.Biochem. Biophys. Res. Commun. 122265–269.

  13. Lutz, R. A., Cruciana, R. A., Munson, P. J., and Rodbard, D. (1985b). Mu1: A very high affinity subtype of enkephalin binding sites in rat brain.Life Sci. 362233–2238.

  14. Moskowitz, A. S., and Goodman, R. R. (1985a). Autoradiographic distribution of mu1 and mu2 opioid binding in the mouse central nervous system.Brain Res. 360117–129.

  15. Moskowitz, A. S., and Goodman, R. R. (1985b). Autoradiographic analysis of mu1, mu2 and delta opioid binding in the central nervous system of the C57BL/6BY and CXBK (opioid receptor-deficient) mice.Brain Res. 360108–116.

  16. Nishimura, S. L., Recht, L. D., and Pasternak, G. W. (1984). Biochemical characterization of high affinity3H-opioid binding: Further evidence for mu1 sites.Mol. Pharmacol. 2529–37.

  17. Pasternak, G. W. (1986). Multiple mu opiate receptors: Biochemical and pharmacological evidence for multiplicity.Biochem. Pharmacol. 35361–364.

  18. Pasternak, G. W., and Wood, P. L. (1986). Multiple mu opiate receptors.Life Sci. 381889–1898.

  19. Pasternak, G. W., Childers, S. R., and Snyder, S. H. (1980). Opiate analgesia: Evidence for mediation by a subpopulation of opiate receptors.Science 208514–516.

  20. Spiegel, K., and Pasternak, G. W. (1984). Meptazinol: A novelµ 1 selective opioid analgesic.J. Pharmacol. Exp. Ther. 228414–419.

  21. Turner, P. (1985). Clinical pharmacology of meptazinol.Postgrad. Med. J. 6113–16.

  22. Wolozin, B. L., and Pasternak, G. W. (1981). Classification of multiple morphine and enkephalin binding sites in the central nervous system.Proc. Natl. Acad. Sci. USA 786181–6185.

  23. Young, W. S., and Kuhar, M. J. (1979). A new method for receptor autoradiography:3H-Opioid receptors in rat brain.Brain Res. 179255–270.

Download references

Author information

Correspondence to Gavril W. Pasternak.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Adler, B.A., Goodman, R.R. & Pasternak, G.W. Quantitative autoradiographic distribution of meptazinol-sensitive binding sites in rat brain. Cell Mol Neurobiol 8, 471–476 (1988). https://doi.org/10.1007/BF00711230

Download citation

Key words

  • opiate receptor
  • morphine
  • meptazinol
  • mu1 receptor
  • autoradiography