FURUKAWA Yasue Hiroshima University, Faculty of Integrated Arts and Sciences, Professor, 総合科学部, 教授 (40209169)
MINAKATA Hiroyuki Suntory Institute for Bioorganic Research, Division of Biomolecular Research, General Manager and Executive Researcher, 部長研究員 (90150143)
HORIGUCHI Toshihiro National Institute for Environmental Studies, Research Center for Environmental Risk, Special Senior Researcher, 主任研究員 (30260186)
|Budget Amount *help
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2004: ¥2,200,000 (Direct Cost: ¥2,200,000)
To elucidate the neuropeptide system that regulates the reproductive activity of prosobranch gastropods, structures and physiological functions of a prosobranch, Thais clavigera, were investigated. Using the peptidic extract of the nervous tissues of the animal as the starting material, we identified more than thirty of bioactive materials. About a half of them were identified as peptides. The peptides includes the novel peptides such as AAamide and GKWamide, as well as previously known peptides such as FMRFamide, FRFamide and WWamide. Most of the peptides modified the contractile activities of reproductive organs, including the penial complex, the capsule gland and the prostate gland. For example, FMRFamide and tachykinin induced the contraction of the penial complex, while WWamide inhibited the action. When the paraffin thin sections of Thais central nervous system was immunostained with the eight specific antibodies to the respective peptides (GKWamide,FRFamide,TK,FMRFamide,ALP,WWamide,AAamide,APGWamide,TERP), positive signals were found in the considerable numbers of neurons. FRFamide positive neurons were abundant in the cerebral ganglia, and GKWamide positive neurons were found in subesophageal ganglia. Moreover, FRFamide positive nerve processes were densely distributed around the prostate and capsule glands. These results suggest that the Thais peptides mediate the nervous control of the reproductive system of the animal. Thus, it is likely that a complex neuropeptide system regulates the reproductive activity of the animal. Recently, it is known that the environmental organotins such as tributyltin and triphenyl tin induce masculinization of female prosobranchs (imposex). The malfunctioning of neuropeptide system by the compounds could be one of the mechanism for the phenomenon. Our findings provides fundamentals for the evaluation of the hypothesis.