Antinociception induced by beta-lactotensin, a neurotensin agonist peptide derived from beta-lactoglobulin, is mediated by NT2 and D1 receptors.
In this study, we examined the antinociceptive effect of beta-lactotensin, a neurotensin agonist that has been isolated from the chymotrypsin digest of beta-lactoglobulin as an ileum-contracting peptide. Beta-lactotensin showed naloxone-insensitive antinociceptive activity by the tail-pinch test after i.c.v. (200 nmol/mouse) or s.c. (300 mg/kg) administration in ddY mice. Tolerance was not developed to antinociception induced by beta-lactotensin after repeated s.c. administration for 5 days. The antinociceptive activity of beta-lactotensin was blocked by treatment with the neurotensin NT2 receptor antisense ODN, while treatment with the NT1 receptor antisense ODN had no effect. The antinociceptive activity was also blocked by a dopamine D1 receptor antagonist, SCH23390 (1 microg/mouse, i.c.v.), while a D2 receptor antagonist, raclopride (0.5 microg/mouse, i.c.v.), did not block the activity. These results indicate that the antinociceptive activity of beta-lactotensin is mediated by NT2 and D1 receptors.
Yamauchi
Rena
R
Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, 611-0011, Japan.
Sonoda
Soushi
S
Jinsmaa
Yunden
Y
Yoshikawa
Masaaki
M
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007782:Lactoglobulins; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology*; D020891:Raclopride / Q000494:pharmacology; D017447:Receptors, Dopamine D1 / Q000819:agonists*; D018028:Receptors, Neurotensin / Q000819:agonists*
D000700:Analgesics; D001552:Benzazepines; D018492:Dopamine Antagonists; D007782:Lactoglobulins; C490984:Ntsr2 protein, mouse; D016376:Oligonucleotides, Antisense; D009842:Oligopeptides; D017447:Receptors, Dopamine D1; D018028:Receptors, Neurotensin; C102984:beta-lactotensin; D020891:Raclopride