1.
Andersson, Hanna, Dr. 1979-, et al.
(författare)
Ligands to the (IRAP)/AT4 receptor encompassing a 4-hydroxydiphenylmethane scaffold replacing Tyr2
2008
Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 16:14, s. 6924-6935
Tidskriftsartikel (refereegranskat) abstract
Analogues of the hexapeptide angiotensin IV (Ang IV, Val(1)-Tyr(2)-Ile(3)-His(4)-Pro(5)-Phe(6)) encompassing a 4-hydroxydiphenylmethane scaffold replacing Tyr(2) and a phenylacetic or benzoic acid moiety replacing His(4)-Pro(5)-Phe(6) have been synthesized and evaluated in biological assays. The analogues inhibited the proteolytic activity of cystinyl aminopeptidase (CAP), frequently referred to as the insulin-regulated aminopeptidase (IRAP), and were found less efficient as inhibitors of aminopeptidase N (AP-N). The best Ang IV mimetics in the series were approximately 20 times less potent than Ang IV as IRAP inhibitors. Furthermore, it was found that the ligands at best exhibited a 140 times lower binding affinity to the membrane-bound IRAP/AT4 receptor than Ang IV. Although the best compounds still exert lower activities than Ang IV, it is notable that these compounds comprise only two amino acid residues and are considerably less peptidic in character than the majority of the Ang IV analogues previously reported as IRAP inhibitors in the literature.
2.
Fransson, Rebecca, et al.
(författare)
Small peptides mimicking substance P (1-7) and encompassing a C-terminal amide functionality
2008
Ingår i: Neuropeptides. - : Elsevier BV. - 0143-4179 .- 1532-2785. ; 42:1, s. 31-37
Tidskriftsartikel (refereegranskat) abstract
Some of the biological effects demonstrated after administration of substance P (SP) in vivo can indirectly be attributed to the fragmentation of the undecapeptide to its N-terminal bioactive fragment SP1–7. This heptapeptide (H-Arg-Pro-Lys-Pro-Gln-Gln-Phe-OH) is a major bioactive metabolite from SP that frequently exerts similar biological effects as the parent peptide but also, in several cases, completely opposite actions. Specific binding sites for the heptapeptide SP1–7 that are separate from the SP preferred NK receptors have been identified. In this study we demonstrate that (a) the C-terminal part of the SP metabolite SP1–7 is most important for binding as deduced from an Ala scan and that a replacement of Phe7 for Ala is deleterious, (b) truncation of the N-terminal amino acid residues of SP1–7 delivers peptides with retained binding activity, although with somewhat lower binding affinities than SP1–7 and (c) a C-terminal amide group as a replacement for the terminal carboxy group of SP1–7 and for all of the truncated ligands synthesized affords approximately 5–10-fold improvements of the binding affinities.
3.
Svensson, Anne-Lie, et al.
(författare)
Reversal of opiate-induced apoptosis by human recombinant growth hormone in murine foetus primary hippocampal neuronal cell cultures
2008
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 105:20, s. 7304-7308
Tidskriftsartikel (refereegranskat) abstract
Previous studies have shown that chronic opiates may inhibit cell growth and trigger apoptosis leading to impaired cognitive capabilities in both humans and other mammals. In contrast, growth hormone (GH) has been demonstrated to stimulate cell growth and counteract apoptosis. GH has also been shown to improve learning and memory in both human and rodents. In this work, we demonstrate that GH may reverse opiate-induced apoptosis in cells derived from prenatal mouse hippocampus. Primary hippocampal cell cultures derived from 16-day-old fetal mouse neurons were treated with morphine for 7 days during growth in the absence or presence of recombinant human GH (rhGH). The release of lactate dehydrogenase (LDH) into the culture media and the level of cleaved caspase-3 were measured. Results indicate that morphine (15 mu M) decreased the cell content in a concentration-dependent manner and increased LDH release and caspase-3 activity. Thus, fetal mouse neurons treated with morphine showed less viability compared with controls. Interestingly, the addition of rhGH (11 mu M) counteracted the morphine-induced effect on the cell density. Furthermore, the hormone attenuated the effects on LHD release and caspase-3 activity elicited by morphine. These results suggest that the hormone is capable of preventing or even repairing morphine-induced damage to hippocampal cells.
