title: Involvement of spinal mu1-opioid receptors on the Tyr-d-Arg-Phe-sarcosine-induced antinociception.
abstract: The involvement of spinal mu-opioid receptor subtypes on the antinociception induced by i.t.-administered Tyr-D-Arg-Phe-sarcosine (TAPS), a N-terminal tetrapeptide analog of dermorphin, was determined in mice tail-flick test. Intrathecal administration of TAPS produced the marked inhibition of the tail-flick response in a dose-dependent manner. The antinociception induced by TAPS was completely eliminated by i.t.-co-administration of Tyr-D-Pro-Phe-Phe-NH2 (D-Pro2-endomorphin-2), the mu1-opioid receptor antagonist, whereas i.t. co-treatment with Tyr-D-Pro-Trp-Phe-NH2 (D-Pro2-endomorphin-1) or Tyr-D-Pro-Trp-Gly-NH2 (D-Pro2-Tyr-W-MIF-1), the mu2-opioid receptor antagonists, did not affect the TAPS-induced antinociception. In contrast, the antinociception induced by i.t.-administered [D-Ala2,N-MePhe4,Gly-ol5]enkephalin was significantly attenuated by i.t.-co-administration of D-Pro2-endomorphin-1 or D-Pro2-Tyr-W-MIF-1, but not D-Pro2-endomorphin-2. These results suggest that TAPS may stimulate spinal mu1-opioid receptors to produce the antinociception.
authors.affiliation: Department of Physiology and Anatomy, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Mizoguchi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Nakayama
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Watanabe
authors.forename: Kanenori
authors.initials: K
authors.lastname: Ito
authors.forename: Wataru
authors.initials: W
authors.lastname: Sakurada
authors.forename: Toshiki
authors.initials: T
authors.lastname: Sawai
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Fujimura
authors.forename: Takumi
authors.initials: T
authors.lastname: Sato
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Sakurada
authors.forename: Shinobu
authors.initials: S
authors.lastname: Sakurada
mesh_terms: D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)- / Q000008:administration & dosage / Q000494:pharmacology; D006358:Hot Temperature / Q000009:adverse effects; D006930:Hyperalgesia / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D007278:Injections, Spinal; D009075:MSH Release-Inhibiting Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D008297:Male; D051379:Mice; D009842:Oligopeptides / Q000008:administration & dosage / Q000494:pharmacology*; D010147:Pain Measurement / Q000379:methods; D020033:Protein Isoforms / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D017450:Receptors, Opioid, mu / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism
chemical_list: D000700:Analgesics; D000701:Analgesics, Opioid; D009842:Oligopeptides; D020033:Protein Isoforms; D017450:Receptors, Opioid, mu; C105293:endomorphin 1; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; C077532:tyrosyl-prolyl-tryptophyl-glycinamide; C105294:endomorphin 2; C053418:tyrosyl-arginyl-phenylalanyl-sarcosine; D009075:MSH Release-Inhibiting Hormone