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The presence of μ-, δ- and κ-binding sites in homogenates of guinea-pig brain was demonstrated by the use of selective labelling techniques. In saturation experiments, the tritiated ligands [^3H]-[D-Ala^2, MePhe^4, Gly-ol^5]enkephalin, [^3H]-dihydromorphine, [^3H]-morphine and [^3H]-dihydronormorphine labelled only the μ-binding site. The δ-binding site could be labelled selectively with [^3H]-[D-Pen^2, D-Pen^5]enkephalin. However, the less selective δ-ligand, [³H]-[D-Ala², D-Leu⁵] enkephalin, could only be used when its μ-binding was blocked with the unlabelled μ-ligand [D-Ala², MePhe⁴, Gly-ol⁵]enkephalin. Selective labelling of the κ-binding site was more of a problem since the non-selective ligands [^3H]-etorphine, [^3H]-(±)-ethylketazocine and [³H]-(-)-bremazocine bind to the μ-, δ- and κ-sites. Therefore, the κ-binding site could only be labelled selectively when the binding of the tritiated ligands to the μ- and δ-sites was prevented by addition of the unlabelled μ-ligand [D-Ala^2, MePhe^4, Gly-ol^5]enkephalin and the unlabelled δ-ligand [D-Ala², D-Leu⁵]enkephalin. By analysis of the saturation curves obtained using these selective labelling techniques, the proportion of binding sites in homogenates of guinea-pig brain at 25°C was 24% μ-sites; 32% δ-sites and 44% κ-sites. The selective labelling techniques were also used to label the μ, δ- and κ-sites in displacement assays. The compounds with the highest degree of preference for each binding site were: for the μ-site, [D-Ala^2, MePhe^4, Gly-ol^5]enkephalin and Tyr-Pro-MePhe-D-Pro-NH_2; for the δ-site, [D-Pen², L-Pen⁵]enkephalin, [D-Pen², D-Pen⁵]enkephalin and ICI 174864 and for the κ-site, U-50,488H and U-69,593. As far as antagonists were concerned, naloxone displayed the highest preference for the μ-binding site and Mr 2266 had a preference for the κ-binding site but neither compound was highly selective unlike the δ-antagonist ICI 174864. The effect of pre-incubation with β-funaltrexamine on opioid binding was investigated in homogenates of guinea-pig brain and myenteric plexus-longitudinal muscle.

Thesis (M.A.)--University of Hawaii at Manoa, 2004. / Includes bibliographical references (leaves 133-139). / v, 139 leaves, bound map 29 cm

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xx, 245 p.; also includes graphics. Includes bibliographical references (p. 206-216).

Thesis (M.S.)--University of Wisconsin--Madison, 1962. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 57-60).

Thesis (D. Min.)--Columbia International University, 1998.

Added t.p. with thesis statement inserted. / Bibliography: leaves 25-28.

Thesis (Ph. D.)--University of Pittsburgh, 1956. / Photocopy. Ann Arbor, Mich. : University Microfilms International, 1981. -- 21 cm. Includes bibliographical references (leaves 131-137).