title: Changes of MAO-A and MAO-B Expressions in the Placenta of MPTP or MPP(+) Treated Mice.
abstract: In the present study, we evaluated the influence of intraperitoneal administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or 1-methyl-4-phenylpyridinium (MPP(+)) on the placenta. There was no increase in apoptotic cells in the placentas of C57BL/6 mice treated with 25.0 mg/kg MPTP or 17.1 mg/kg MPP(+), indicating that a single injection of the chemicals may induce very slight cytotoxicity in the placenta at 12 hr after administration. The decrease in the expression of monoamine oxidase (MAO)-A in the labyrinth zone and that of MAO-B in the basal zone may be due to the decrease in cell activity, whereas the increase of MAO-B expression in the labyrinth zone after MPTP treatment may be due to a responsive reaction caused by MPTP, one of the substrates of MAO-B. The results represent histological evidence that MAO-B may be involved in the metabolism of MPTP to MPP(+) in the labyrinth zone of the mouse placenta. In the present study, no increase in apoptotic cells indicates that MPTP and MPP(+) are hardly toxic to the placenta, and the histological change in MAO-B expression may indicate the possibility of involvement of placental MAO-B in MPTP metabolism.
authors.affiliation: Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan ; Pathology Group, Toxicology and Pharmacokinetics Laboratories, Pharmaceutical Research Laboratories, Toray Industries, Inc., 6-10-1 Tebiro, Kamakura-shi, Kanagawa 248-8555, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Sai
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Uchida
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakayama
keywords: C57BL/6 mice; MAO-B (monoamine oxidase B); MPP+(1-methyl-4-phenylpyridinium); MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine); placenta