http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Diprotin A, an inhibitor of dipeptidyl aminopeptidase IV (EC3.4.14.5) produces naloxone-reversible analgesia in rats
The dipeptidyl aminopeptidase IV (DP IV) inhibitor Diprotin A produces st full, dose-dependent, short-lasting and naloxone- reversible analgesia in the rat tail-flick test when given intracerebroventricularly, with an ED50 of 295 nmol/rat but it has no direct opioid agonist activity in the longitudinal muscle strip of guinea-pig ileum bioassay. Two of the potential DP IV substrates, morphiceptin and endomorphin 1, identified recently in bovine brain were also analgesic given by similar route. The action of endomorphin 1 was more potent (ED50 = 7.9 nmol/rat) and slightly but significantly more sustained than that of Diprotin A. Diprotin A neither potentiated nor prolonged the effect of a marginally analgesic dose of endomorphin 1. The distinct time course and the lack of potentiation indicate that in the analgesic effect of Diprotin A. in rats the protection of a brain Tyr-Pro-peptide other than endomorphin 1 is involved.