Graduation date: 1999

Graduation date: 1996

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 7 uppsatser.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 140-150).

During my research career in Prof. V.J.Hruby's laboratory I worked on two different projects. The first project, which was initiated by the author, was planned to serve the need of our laboratory for a novel method of peptide cyclization. This method was planned to use recent advances in Pd0-catalyzed asymmetric synthesis combined with the structural richness offered by the Baylis-Hillman chemistry which could open new ways to diverse areas of drug design, molecular immunology and chemotherapy. This approach would provide cyclic peptides featuring N-alkylated amino acids that would confer high resistance to degradation by proteases. Because of numerous synthetic problems imposed, this strategy was not of considerable current use in peptide synthesis, especially on solid supports. However, despite a substantial amount of effort invested, this method faced serious drawbacks such as multistep synthesis and side reactions when applied to solid supports. Moreover, recent introduction of microwave technology which has helped to solve a great number of problems has led to a renaissance in the classical lactam and thioester bond cyclizations which overshadowed our quest for a novel methodology. The second project was focused on application of 4-anilidopiperidines for the synthesis of chimeric bioactive peptides. It was an effort towards the development of novel analgesics with reduced toxicity and enhanced potency. This project linked small molecule and multimeric ligand designs that were ongoing in our laboratory at the time. Major accomplishments in this project were made possible by successful resolution of several research challenges. I was able to find a straightforward, convenient and economical approach for the synthesis of novel analogues on a solid support. These developments led to novel compounds which showed substantial increases in their binding affinity relative to corresponding opioid analogues. To illustrate, compounds PET25, 26, 27, 29, 30, 31, and 32 showed high bioactivity and sub-nanomolar binding affinity to opioid receptors. Most of the peptides generated in the second project are still being investigated for their biological activities by our colleagues at the Department of Pharmacology, but the results to date indicate that some highly potent novel compounds have been made.

Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 5 uppsatser.

Thesis (Ph. D.)--Cornell University, May, 2008. / Vita. Includes bibliographical references (leaves 143-165).

The midbrain periaqueductal gray matter (PAG) is an important brain region for the coordination of μ-opioid-induced pharmacological actions. The present study was designed to determine whether newly isolated μ-opioid peptide endomorphins can activate G proteins through μ-opioid receptors in the PAG by monitoring the binding to membranes of the non-hydrolyzable analog of GTP, guanosine-5'-O-(3-[35S]thio)triphosphate ([35S]GTPγS). An autoradiographic [35S]GTPγS binding study showed that both endomorphin-1 and -2 produced similar anatomical distributions of activated G proteins in the mouse midbrain region. In the mouse PAG, endomorphin-1 and -2 at concentrations from 0.001 to 10 μM increased [35S]GTPγS binding in a concentration-dependent manner and reached a maximal stimulation of 74.6 ± 3.8 and 72.3 ± 4.0%, respectively, at 10 μM. In contrast, the synthetic selective μ-opioid receptor agonist [D-Ala2,NHPhe4,Gly-ol]enkephalin (DAMGO) had a much greater efficacy and produced a 112.6 ± 5.1% increase of the maximal stimulation. The receptor specificity of endomorphin-stimulated [35S]GTPγS binding was verified by coincubating membranes with endomorphins in the presence of specific μ-, δ- or κ-opioid receptor antagonists. Coincubation with selective μ-opioid receptor antagonists β- funaltrexamine or D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Phe-Thr-NH2 (CTOP) blocked both endomorphin-1 and-2-stimulated [35S]GTPγS binding. In contrast, neither δ- nor κ-opioid receptor antagonist had any effect on the [35S]GTPγS binding stimulated by either endomorphin-1 or -2. These findings indicate that both endomorphin-1 and -2 increase [35S]GTPγS binding by selectively stimulating μ-opioid receptors with intrinsic activity less than that of DAMGO and suggest that these new endogenous ligands might be partial agonists for μ-opioid receptors in the mouse PAG.

An investigation of the interaction of stable opioid/ligands and unstable opioid peptides with opioid receptors in guinea pig brain, guinea pig myenteric plexus and mouse vas deferens has been carried out. The initial aim of the study was to further characterise K opioid receptors, using binding assays and isolated tissue bioassays. The second aim was to determine the true affinity and potency of small dynorphin peptides for the K opioid receptor and to determine if metabolism of the peptides to non K opioid receptor-preferring products contributes to their observed in vitro pharmacology.