To investigate the role of the carboxyl group in deltorphin molecules, we have synthesized three new analogues in which the acidic amino acid residues in position 4 of the deltorphins were replaced by non-acidic but hydrophilic amino acids residues. The three analogues, [Ser4]-, [Gln4]-, and [Cys4]-deltorphin, all are as potent or more potent than either deltorphin I or II at delta opioid receptors and possess good delta selectivities. The excellent correlation between their in vitro delta receptor potencies and their intrathecal antinociception activity forms a strong argument for involvement of those receptors in spinal nociceptive modulation in the rats.
|Original language||English (US)|
|Number of pages||8|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Nov 14 1991|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology