Jpn. J. Pharmacol. 84 (3), 259-265 (2000)


Behavioral and Pharmacological Studies on Gluten Exorphin A5, a Newly Isolated Bioactive Food Protein Fragment, in Mice

Masakatsu Takahashi1,*, Hiroko Fukunaga1, Hiroshi Kaneto2, Shin-ichi Fukudome3 and Masaaki Yoshikawa4

1Department of Pharmacoinformatics, School of Pharmaceutical Sciences, Nagasaki University and 2Emeritus Professor, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan
3Food Research Laboratory, Nisshin Flour Milling Co., Ltd., Ohimachi, Saitama 356-8511, Japan
4Research Institute for Food Scicence, Kyoto University, Uji, Kyoto 611-0011, Japan
*Corresponding author.╩╩Present affiliation for correspondence: Department of Analytical Research for Pharmacoinformatics, Graduate School of Pharmaceutical Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan
FAX:+81-95-844-6774, E-mail: takahashi@net.nagasaki-u.ac.jp

Abstract: Central effects of gluten exorphin╩A5 (Gly-Tyr-Tyr-Pro-Thr), a fragment from wheat gluten, were studied on the pain-inhibitory system, emotionality and learning/memory processes in mice. Orally administered gluten exorphin╩A5 produced neither an antinociceptive effect nor an effect on morphine analgesia. Intracerebroventricularly (i.c.v.) administered gluten exorphin╩A5 produced mild but significant antinociception in a dose-depepndent manner, while not affecting the morphine analgesia. On the other hand, oral gluten exorphin╩A5 suppressed the endogenous pain-inhibitory system, i.e., antinociception induced by socio-psychological- (PSY-) stress (SIA) using a communication box; intraperitoneal gluten exorphin╩A5 abolished both footshock- (FS-) stress-induced antinociception (SIA) and PSY-SIA; and i.c.v. gluten exorphin╩A5 suppressed FS-SIA, but rather potentiated PSY-SIA. This peptide given by these routes was without effect on forced swim-SIA. In addition, oral gluten exorphin╩A5 tended to prolong the retention time on open arms in the elevated plus-maze test. Finally, oral gluten exorphin╩A5 when given during the post-training period of learning/memory processes significantly increased the latency into the dark compartment in the one-trail step-though type passive avoidance test, indicating that the peptide also facilitates the acquire/consolidation process of learning/memory. Thus, gluten exorphin╩A5 has been found to produce various effects not only in the peripheral nervous systems but also in the central nervous system.

Keywords: Gluten exorphin╩A5, Stress-induced antinociception, Emotionality, Learning/memory process, Morphine


Copyrightę The Japanese Pharmacological Society 2000

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