Momoko Miyakawa

Synaptic plasticity to estrogen in the lateral septum of the adult male and female rats.

There is no sex difference in the number of axodendritic synapses in the lateral septum of adult rats. However, the treatment of adult females with estradiol (E2) for 4 weeks increases significantly the number of synapses, whereas E2 treatment fails to increase the synaptic number in males, suggesting a possible sexually dimorphic synaptic response to estrogen.

Corticosterone stimulates the development of preoptic catecholamine neurons in tadpoles Bufo bufo japonicus.

SummaryIn Bufo bufo japonicus catecholamine neurons in the preoptic recess organ (PRO) became detectable at the metamorphic climax by formaldehyde-induced fluorescence (Falck-Hillarp technique). In hypophysectomized tadpoles metamorphosis was inhibited and no fluorescent neurons appeared in the PRO. Implantation of a pituitary graft to the hypophysectomized tadpoles induced metamorphosis and development of PRO catecholamine neurons. Administration of corticosterone to hypophysectomized tadpoles resulted in the development of PRO catecholamine neurons in spite of the unmetamorphosed state. On the other hand, prolactin administration had no effect on the PRO neurons of hypophysectomized tadpoles. From these results, in conjunction with our previous results indicating that thyroxine treatment induces development of the PRO catecholamine neurons in thyroidectomized animals but not in hypophysectomized animals, it is concluded that corticosterone is a primary hormone for the development of PRO catecholamine neurons in toad tadpoles.

A monoclonal thymocytotoxic autoantibody from autoimmune-disease-prone New Zealand Black mouse recognizes β-tubulin in neural tissue

On the basis of our previous report that a thymocytotoxic monoclonal autoantibody (NTA260) derived from a New Zealand Black mouse reacts with brain tissues as well as lymphoid cells, the neuronal antigen reacting with this antithymocyte antibody was characterized in the present experiment. Double staining of cultured brain cells with NTA260 and anti-tubulin antibody revealed that both staining patterns closely resembled each other. NTA260 reacted with purified tubulin molecules on Western blotting. Two-dimensional gel electrophoresis of the whole lysate of embryonic mouse brain revealed that NTA260 stained the spot corresponding to that of beta-tubulin but not that of alpha-tubulin. These results suggest that beta-tubulin is a prominent neuronal antigen recognized by NTA260.

A thymocytotoxic autoantibody reacts with the mouse brain cells in culture

Autoimmune-prone New Zealand Black mice produce a large amount of autoantibodies cytotoxic for thymocytes (natural thymocytotoxic autoantibodies, NTA). A monoclonal NTA (NTA260) has been found to react with brain tissues as well as the cell surface of thymocytes. We investigated the expression of NTA 260 antigen in the primary culture of fetal brain cells. NTA260 labeled strongly the cytoplasm of nerve cells after fixation, but failed to stain the living cells. Western blot analysis revealed that NTA260 recognized predominantly a band at approximately 53 kDa in brain and thymic extracts. These findings indicate that neuronal NTA260 antigen, which has a molecular mass similar to that of thymocytes, is likely an intracellular component.

Origin of PSA-NCAM expressing blood vessels in the developing forebrain of avian embryo

P3-e25 Lineage tracing of Nkx2.2-expressing cells by novel genetically-defined lineage tracing method in chick spinal cord Hitoshi Goto 1,2 , Katsuhiko Ono 1,2,3, Hirohide Takebayashi 2,3,4, Hidekiyo Harada 5, Harukazu Nakamura 5, Kazuhiro Ikenaka 2,3 1 Department of Biology, Kyoto Prefectual University of Medicine, Kyoto 2 Div. of Neurobiol. and Bioinformatics, National Institute for Physiological Sciences, Okazaki 3 Sokendai, Hayama 4 Department of Morphological Neural Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 5 Dep. of Molecular Neurobiology, Graduate School of Life Sciences and Institute of Development, Aging and Cancer, Tohoku University, Miyagi

Spatial and temporal distribution patterns of PSA-NCAM positive pericytes of the embryonic brain

noids suppress this GABA release. In the present study, we investigated involvement of the endocannabinoid metabolic pathway and the cannabinoid CB2 receptor in PC dendrogenesis. Using several endocannabinoid metabolic enzyme inhibitors, we show that 2-arachidonoylglycerol (2-AG), one of the endocannabinoids, controls PC dendrogenesis; an inhibitor for the 2-AG synthesizing enzyme promotes PC dendritic development, whereas that for the 2-AG degrading enzyme prevents dendrite elongation of PCs. Next, using CB2-selective and non-selective ligands, we found a possibility that the CB2 receptor may contribute to development of PC dendrites. In addition, we also report results that receptors for glycine, another inhibitory neurotransmitter, may play a role in PC dendrogenesis.