Abstract
The conformationally constrained analogues of phenylalanine, tetrahydroisoquinoline-3-carboxylic acid (Tic), Sic, Hic and Nic, and the new amino acid Xic have been incorporated into a potent and highly selective cholecystokinin-2 (CCK(2)) receptor antagonist (2) in place of the phenylalanine residue, producing compounds 15a-e. High selectivities for CCK(2) over CCK(1) were observed for compounds 15a-e. The in vitro profile of the analogue containing the Nic residue (15d) was identical to that of compound 2, whereas the alternative conformational constraints resulted in a significant loss of affinity. The apparent advantage of Nic in the context of these CCK(2) ligands was subsequently demonstrated to be statistically significant.
MeSH terms
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Animals
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Cerebral Cortex / drug effects
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Cerebral Cortex / metabolism
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Gastric Mucosa / metabolism
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Guinea Pigs
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Heterocyclic Compounds, 2-Ring / chemical synthesis*
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Heterocyclic Compounds, 2-Ring / chemistry
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Heterocyclic Compounds, 2-Ring / pharmacology
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In Vitro Techniques
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Isoquinolines / chemistry
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Ligands
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Mice
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Pancreas / drug effects
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Pancreas / metabolism
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Phenylalanine / chemistry*
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Rats
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Receptor, Cholecystokinin B
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Receptors, Cholecystokinin / antagonists & inhibitors*
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Stomach / drug effects
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Tetrahydroisoquinolines*
Substances
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Heterocyclic Compounds, 2-Ring
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Isoquinolines
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Ligands
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Receptor, Cholecystokinin B
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Receptors, Cholecystokinin
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Tetrahydroisoquinolines
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1,2,3,4-tetrahydroisoquinoline carboxylic acid
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Phenylalanine