Peripheral non-opioid analgesic effects of kyotorphin in mice.
Bradykinin (BK) given into the plantar (i.pl.) of the mouse hind-limb produced a flexor response. The flexor responses were dependent on BK doses (0.02-20 pmol, i.pl.), and were completely abolished by Hoe140, a B2-type BK receptor antagonist. Kyotorphin, an analgesic neuropeptide which shows enkephalin release in brain slices, produced a dose-dependent reduction of the BK-induced nociceptive responses in ranges of 10 pmol to 1 nmol (i.pl.). Such analgesic effects of kyotorphin were reversed by leucine-arginine, a specific kyotorphin receptor antagonist, but not by naloxone. The kyotorphin-analgesia was also abolished by pertussis toxin (PTX) pretreatment. These results suggest that peripheral analgesic effects of kyotorphin are mediated through mechanisms of kyotorphin specific receptor and PTX-sensitive Gi/Go, and that the enkephalin release is not necessary for this analgesia.
Inoue
M
M
Department of Molecular Pharmacology and Neuroscience, Nagasaki University School of Pharmaceutical Sciences, Japan.
Nakayamada
H
H
Tokuyama
S
S
Ueda
H
H
D000344:Afferent Pathways / Q000187:drug effects; D000700:Analgesics; D000818:Animals; D065168:Bradykinin Receptor Antagonists; D004305:Dose-Response Relationship, Drug; D004723:Endorphins / Q000494:pharmacology*; D008297:Male; D051379:Mice; D010146:Pain / Q000503:physiopathology*
D000700:Analgesics; D065168:Bradykinin Receptor Antagonists; D004723:Endorphins; C019448:kyotorphin