Autoradiographic distribution of mu and delta opiate receptors in rat brain using highly selective ligands

• Published in: Life sciences (1973) Vol. 33 Suppl 1; p. 227
• Main Authors: Quirion, R, Zajac, J M, Morgat, J L, Roques, B P
• Format: Journal Article
• Language: English
• Published: Netherlands 1983
• Subjects: Animals; Autoradiography; Brain - metabolism; Rats; Receptors, Opioid - metabolism; Receptors, Opioid, delta; Receptors, Opioid, mu; Tissue Distribution; Tritium
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/0024-3205(83)90484-8

We have characterized the autoradiographic distribution of mu and delta opiate receptors in rat brain using [3H]-Tyr-D-Ala-Gly-NMe-Phe-Gly-ol (DAGO) and [3H]D-Thr2, Thr6leu-enkephalin (DTLET), two highly selective ligands for mu and delta opiate receptors, respectively. Both ligands label an apparent single class of sites. Ligand selectivity shows that [3H]DAGO and [3H]DTLET are more selective ligands for their respective receptors than [3H]dihydromorphine (DHM) and [3H][D-Ala2,D-Leu5]enkephalin (DADLE). Autoradiographically, mu opiate receptors are highly discretely distributed in certain areas. High densities are found in "patches" in caudate-putamen, nucleus accumbens, cingulate cortex, habenula, various thalamic nuclei, amygdala, superior colliculus, and interpeduncular nucleus. Delta opiate receptors are mostly concentrated in the external plexiform layers of the olfactory bulb, caudate-putamen, olfactory tubercule, claustrum, and deep layers (layers V and VI) of the cortex. Since [3H]DAGO and [3H]DTLET are more selective ligands for their respective opiate receptor subtypes, they should be better ligands to characterize the fine distribution of mu and delta opiate receptors.