PT  - JOURNAL ARTICLE
AU  - Bochet, P
AU  - Icard-Liepkalns, C
AU  - Pasquini, F
AU  - Garbay-Jaureguiberry, C
AU  - Beaudet, A
AU  - Roques, B
AU  - Rossier, J
TI  - Photoaffinity labeling of opioid delta receptors with an iodinated azido-ligand: [125I][D-Thr2,pN3Phe4,Leu5]enkephalyl-Thr6.
DP  - 1988 Oct 01
TA  - Molecular Pharmacology
PG  - 436--443
VI  - 34
IP  - 4
4099  - http://molpharm.aspetjournals.org/content/34/4/436.short
4100  - http://molpharm.aspetjournals.org/content/34/4/436.full
SO  - Mol Pharmacol1988 Oct 01; 34
AB  - The photoaffinity ligand of the delta opioid receptor Tyr-D-Thr-Gly-pN3Phe-Leu-Thr (azido-DTLET) was iodinated and purified by high performance liquid chromatography. Monoiodo-azido-DTLET displayed a high affinity (KD = 15 nM) and is selective (Kl mu/Kl delta = 9.8) for rat brain delta opioid receptors (for comparison, the corresponding values for tritiated azido-DTLET are KD = 1.66 nM and Kl mu/Kl delta = 27). On rat brain sections, the anatomical distribution of [125I]azido-DTLET binding sites revealed by autoradiography corresponds to that of delta receptors. On rat brain membrane homogenates and NG108-15 hybrid cells, UV irradiation of the receptor-ligand complex results in the irreversible binding to membrane proteins of 14% of the bound radioactivity Gel electrophoresis of [125I]azido-DTLET-labeled proteins followed by autoradiography shows a different pattern in rat brain and NG108-15 cells. In rat brain, labeling of two of these proteins, with molecular weights of 44,000 and 34,000, was inhibited by 30 nmol/liter of nonradioactive DTLET, a delta-selective ligand but not by the same concentration of [D-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin, a mu-selective ligand. In NG108-15 cells, this 44-kDa protein was not visualized; the main band was at 33 kDa and disappeared in the presence of levorphanol.