Takeshi Shimahara's research while affiliated with French National Centre for Scientific Research and other places

... MIns has been shown to be increased in trisomic cortical neurons (40% compared to diploid), generated from a trisomic mouse model, obtained by breeding normal females to males with heterozygous Robertsonian translocations of chromosome 16 (which shows large synteny with HSA21) (Acevedo et al., 1997). Elevated levels of mIns have also been found in amniotic fluid of human DS pregnancies (15-18 weeks GA) (Santamaria et al., 2014) SMIT1 is overexpressed in human DS and associated with increased intracellular levels of mIns in adults (Shonk and Ross, 1995;Cárdenas et al., 2017). Given the association of mIns transporters and HSA21, our results, likely reflect an elevation in incorporated intracellular mIns concentration. ...

... It has been shown in a previous paper (Shimahara et al. 1986 ) that transformation of the non-spiking soma into a Ca 2+ -dependent spiking one necessitates the reduction of the outward current, for example by a pre-depolarization to — 50 mV, and cannot be explained by facilitation of a Ca 2+ conductance per se. Moreover, in the present work we have observed (seeFig. ...

... As the use of animals in experimental research is discouraged, H9c2, a clonal myogenic cell line derived from embryonic rat heart, has served as a surrogate for cardiac and skeletal cells and has become an important tool for toxicology [35] and signal transduction studies Interestingly, our array data show that axin-2 (a classical target of the canonical Wnt pathway), a negative regulator of beta-catenin, was suppressed by MR-409, indicating modulation of the beta-catenin pathway. The exact role of beta-catenin in adult cardiac remodeling in vivo is still not understood; however, downregulation of beta-catenin is required for adaptive cardiac hypertrophy. ...

... This drawback has limited the use of those animals to studies of early developmental stages and to the use of primary cell cultures (Galdzicki and Siarey, 2003). In this regard, an interesting development has been the establishment of an immortalized cell line (CTb) derived from the cerebral cortex of a trisomy 16 mouse fetus (Allen et al., 2000Allen et al., , Cárdenas et al., 1999). This cellular model has been well accepted for the study of DS and AD pathologies (for a review, see Saud et al., 2006). ...

... 4;Fuentes at al., 2007). Further, ferrous ion capture study, a cytochemical technique that identifies melanin, was positive in proliferating RCSN-3 cells, and the label was enhanced by differentiation (Arriagada et al., 2002). ...

... Preferential photodegradation can be obtained by controlling the adsorption of the contaminants on the photocatalyst's surface. This can be done by modifying accordingly the temperature [16], the pH [17,18], the presence of ions in the solution [19], the type of solvent [20], or even the UV wavelength [21]. ...

... In dissociated cockroach neurons, multiple conductance states of 11, 17, and 19 pS were detected in GABA receptor single-channel currents (Shimahara et al., 1987;Malecot and Sattelle, 1990). The open-time distributions were fitted to two exponential functions and the close-time distributions were fitted to three exponential functions. ...

... Interestingly, neither TLY (25) nor ␣-LTX (28) affects the number of large dense-core vesicles containing neuropeptides in motor nerve endings despite the depletion of small clear synaptic vesicles. TLY has also been reported to raise the intracellular Ca 2ϩ concentration in cultured mouse hippocampal neurons (29) and adrenal chromaffin cells (27). Simultaneous blockade of L, N, and P/Q voltagedependent Ca 2ϩ channels caused only a minor reduction of TLY-induced catecholamine secretion and little change in Ca 2ϩ signals (27), and removal of extracellular Ca 2ϩ and addition of EGTA or La 3ϩ completely abolished both secretion and Ca 2ϩ signals. ...

... Most of these effects are prevented by ouabain [74]. As a consequence, PTX induces the release of neurotransmitters from motor nerve terminals [75]. ...

... The CTb cell line, derived from the brain cortex of trisomy 16 (Ts16) mice, an animal model of DS, overexpresses most of the genes of the DS critical region (Reeves et al., 1986), including Rcan1 (Lange et al., 2004). Similar to primary culture of central neurons from Ts16 mouse fetus, CTb cells display altered Ca 2+ currents and cytosolic Ca 2+ signals (Cárdenas et al., 1999;Rojas et al., 2008;Acuña et al., 2012). Cholinergic function is also impaired, which is characterized by a reduced fractional acetylcholine release (Fiedler et al., 1994;Allen et al., 2000). ...