Abstract
In the present study, L-prolyl-L-leucyl-glycinamide (1) peptidomimetics 3a-3d and 4a-4d were synthesized utilizing α,α-disubstituted amino acids. These analogues were designed to explore the conformational effects of constraints at the φ3 and ψ3 torsion angles. Constrained conformations were verified by the use of X-ray crystallography and circular dichroism. The effects of Pro-Leu-Gly-NH2 analognes 3a-3d and 4a-4d on enhancing rotational behavior induced by apomorphine in the 6-hydroxydopamine-lesioned animal models of Parkinson's disease were studied. The ability of these peptidomimetics to increase the binding of agonist N-propylnorapomorphine (NPA) to the dopamine D2 receptor was also examined. Extended analogue Pro- Leu-Deg-NH2 was the most active compound of this series. It was 10 times more potent and almost 2 times more effective than 1 in increasing apomorphine-induced rotations (56 ± 15% at 1.0 mg/kg ip) and in enhancing [3H]NPA specific binding (40%).
Original language | English (US) |
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Pages (from-to) | 1441-1447 |
Number of pages | 7 |
Journal | Journal of medicinal chemistry |
Volume | 42 |
Issue number | 8 |
DOIs | |
State | Published - Apr 22 1999 |