Nociceptin (1 - 7) antagonizes nociceptin-induced hyperalgesia in mice.
Nociceptin and its N-terminal fragment, nociceptin (1 7), were administered intrathecally (i.t.) into conscious mice. Nociceptin (3.0 fmol) produced a significant reduction in the nociceptive thermal threshold (hyperalgesia) measured as the tail-flick and paw-withdrawal responses. Nociceptin (1-7), injected i.t., at 150-1200 fmol had no significant effect. However, when nociceptin (1-7) (150 1200 fmol) was injected simultaneously with nociceptin (3.0 fmol), nociceptin-induced hyperalgesia was significantly reduced. Analgesia induced by a high dose (1200 pmol) of nociceptin was not antagonized by co-administration of nociceptin (1-7) (1200 fmol). These results suggest that N-terminal fragments of nociceptin formed endogenously could modulate the hyperalgesic action of nociceptin in the spinal cord.
Sakurada
T
T
Department of Biochemistry, Daiichi College of Pharmaceutical Sciences, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511, Japan.
Sakurada
S
S
Katsuyama
S
S
Sakurada
C
C
Tan-No
K
K
Terenius
L
L
D000595:Amino Acid Sequence; D000818:Animals; D006930:Hyperalgesia / Q000139:chemically induced / Q000517:prevention & control*; D007276:Injections, Intraventricular; D007278:Injections, Spinal; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D018847:Opioid Peptides / Q000037:antagonists & inhibitors*; D010147:Pain Measurement / Q000187:drug effects; D010446:Peptide Fragments / Q000008:administration & dosage / Q000138:chemical synthesis / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects; D011957:Receptors, Opioid / Q000378:metabolism; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism; D000094942:Nociceptin Receptor; D000097629:Nociceptin
D018847:Opioid Peptides; D010446:Peptide Fragments; D011957:Receptors, Opioid; D000094942:Nociceptin Receptor; D000097629:Nociceptin; C000722287:Oprl1 protein, mouse