Science Links Japan | Imbalance in opioid system as a cause of uremic pruritus and effect of a novel .KAPPA. agonist, TRK-820

Imbalance in opioid system as a cause of uremic pruritus and effect of a novel .KAPPA. agonist, TRK-820

Accession number;04A0412018

Title;Imbalance in opioid system as a cause of uremic pruritus and effect of a novel .KAPPA. agonist, TRK-820

Author;KUMAGAI HIROO(Sch. of Med., Keio Univ.) MARUYAMA SHIRO(Niigatakenkeinansogobyoin) EBATA TOSHIYA(Tokyojikeikaiidai Daisanbyoin Hifuka) UTSUMI JUN(Toray Ind., Inc.) SUZUKI HIROMICHI(Saitama Medical School, JPN) TAKAMORI KENJI(Juntendodai Juntendourayasubyoin Hifuka)

Journal Title;Clinic All-round

Journal Code:Z0697A

ISSN:0371-1900

VOL.53;NO.5;PAGE.1678-1684(2004)

Figure&Table&Reference;FIG.5, TBL.2, REF.16

Pub. Country;Japan

Language;Japanese

Abstract;Pruritus is found in about 60% of maintenance hemodialysis patients, and it is an intractable, troublesome complication. The group of Shimojo professor of Niigata Univ. clarified that 40% of maitenance hemodialysis patients is complaining the pruritus from moderate to strong, and that 13% are with a sleep disorder from the pruritus. There has been no drug which is effective for the pruritus except for antihistaminic drug and antiallergic agent until now, since the cause is not known. There are many patients for whom antihistaminic drug does not work. Opioid system as a cause of the pruritus is briefly introduced. As shown in table 1, 4 receptors of .MU. (mu), .DELTA. (delta), .KAPPA. (kappa) and ORL-1 are identified in skin, lymphocyte surface and central nerve, and endogenous and exogenous agonists and antagonists are classified for them. As morphine, a representative .MU. agonist, induces pruritus, the role of endogenous opioid has been noticed as crisis mechanism of pruritus. Danno et al. showed that the concentration of serum methionine/enkephalin, which is an endogenous .MU. agonist, is high in the dialysis patient with pruritus. Peer et al. showed that naltrexone, a .MU. antagonist, significantly suppresses pruritus. However, the group of Mettang disproved the effect of naltrexone, and the effectiveness of .MU. antagonist is negatively considered at present. Therefore we started a research on a series of antipruritic drugs from the viewpoint of the result in neuroscience region that ".KAPPA. opioids suppress the action of .MU. opioids in both central nerve system and peripheral skin".