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47 results on '"Takanashi, Hisanori"'

23. Structure-Activity Study of Intact Porcine Motilin.

Author

HARAMURA, Masayuki, primary, TSUZUKI, Kouichi, additional, OKAMACHI, Akira, additional, YOGO, Kenji, additional, IKUTA, Makoto, additional, KOZONO, Toshiro, additional, TAKANASHI, Hisanori, additional, and MURAYAMA, Eigoro, additional

Published
1999
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42. In vitro Pharmacological Characterization of Mitemcinal (GM-611), the First Acid-Resistant Non-Peptide Motilin Receptor Agonist, in Smooth Muscle of Rabbit Small Intestine.

Author

Takanashi, Hisanori, Yogo, Kenji, Ozaki, Ken-ichi, Koga, Hiroshi, Itoh, Zen, and Ōmura, Satoshi

Subjects
*INTESTINAL diseases, *ANTACIDS, *MOTILIN, *GHRELIN, *ERYTHROMYCIN, *PHARMACOLOGY
Abstract

The pharmacological properties of mitemcinal (GM-611), the first acid-resistant non-peptide motilin agonist, were investigated in the smooth muscle of the rabbit small intestine and compared with porcine motilin (pMTL), erythromycin A (EMA) and its derivatives (EM-523, EM-574 and ABT-229). Mitemcinal, pMTL, EMA, EM-523, EM-574 and ABT-229 produced concentration-dependent contractions with approximately the same maximum contractions in the isolated rabbit duodenum longitudinal strips. The contractile response to mitemcinal or pMTL was competitively inhibited by a selective motilin antagonist, GM-109. The pA2 values for GM-109 as an antagonist of mitemcinal and pMTL showed approximately the same values. However, the concentration-dependent contractile responses to mitemcinal or pMTL were not affected by pretreatment with atropine, tetrodotoxin, hexamethonium, naloxone or tropisetron. The removal of calcium ions from the medium and pretreatment with verapamil greatly suppressed the contractions induced by mitemcinal and pMTL. The contractile response to mitemcinal was not affected by preincubation in acidic solutions, while those of EM-523, EM-574 and ABT-229 were strongly diminished in the same condition. Mitemcinal as well as other motilin agonists displaced 125I-pMTL bound to a homogenate of the rabbit duodenum muscle tissue. The displacement curves of all these compounds were parallel. These results indicate that mitemcinal is a selective and full motilin receptor agonist in the smooth muscle of the rabbit small intestine and that this agent has an excellent acid-resistant property. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Published
2007
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47. Design and synthesis of motilin antagonists derived from the [1-4] fragment of porcine motilin.

Author

Haramura M, Okamachi A, Tsuzuki K, Yogo K, Ikuta M, Kozono T, Takanashi H, and Murayama E

Subjects
Animals, In Vitro Techniques, Muscle Contraction, Muscle, Smooth drug effects, Muscle, Smooth physiology, Peptides, Cyclic chemistry, Peptides, Cyclic pharmacology, Rabbits, Structure-Activity Relationship, Motilin chemistry, Peptide Fragments chemistry, Peptides, Cyclic chemical synthesis, Receptors, Gastrointestinal Hormone antagonists & inhibitors, Receptors, Neuropeptide antagonists & inhibitors
Abstract

A series of cyclic peptides having the general structure H-Phe-c[-N(epsilon)-Lys-X-NH-(CH(2))(n)-CO-] were designed on the basis of structure-activity relationship studies of motilin. All were motilin antagonists. The cyclic peptides, in which X is a 3-tert-butyl-substituted tyrosine residue (H-Phe-c[-N(epsilon)-Lys-Tyr(3-tBu)-beta Ala-] (3), H-Phe-c[-N(epsilon)-Lys-Tyr(3-tBu)-Gly-] (6), H-Phe-c[-N(epsilon)-Lys-Tyr(3-tBu)-Abu-] (7), and H-Phe-c[-N(epsilon)-Lys-Tyr(3-tBu)-Ahx-] (8)) showed potent motilin receptor antagonistic activity in the rabbit smooth muscle (pA(2) > 7). The 3-tert-butyl Tyr was found to be the moiety responsible for enhanced binding to the motilin receptor, while the size of the ring had little importance.

Published
2002
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