Cataplexy
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Research results from T. Matsuki and co-authors update knowledge of science
2009 MAY 19 - (NewsRx.com) -- According to recent research from Saitama, Japan, "Hypothalamic neurons that contain the neuropeptide orexin (hypocretin) play important roles in the regulation of sleep/wake. Here we analyze the in vivo and in vitro phenotype of mice lacking the GABA(B1) gene specifically in orexin neurons (oxGKO mice) and demonstrate that GABA(B) receptors on orexin neurons are essential in stabilizing and consolidating sleep/wake states." "In oxGKO brain slices, we show that the absence of GABAB receptors decreases the sensitivity of orexin neurons to both excitatory and inhibitory inputs because of augmented GABA(A)-mediated inhibition that increases the membrane conductance and shunts postsynaptic currents in these neurons. This increase in GABA(A)-mediated inhibitory tone is apparently the result of an orexin receptor type 1-mediated activation of local GABAergic interneurons that project back onto orexin neurons. oxGKO mice exhibit severe fragmentation of sleep/wake states during both the light and dark periods, without showing an abnormality in total sleep time or signs of cataplexy," wrote T. Matsuki and colleagues. The researchers concluded: "Thus, GABAB receptors on orexin neurons are crucial in the appropriate control of the orexinergic tone through sleep/wake states, thereby stabilizing the state switching mechanisms." Matsuki and colleagues published their study in Proceedings of the National Academy of Sciences of the United States of America (Selective loss of GABA(B) receptors in orexin-producing neurons results in disrupted sleep/wakefulness architecture. Proceedings of the National Academy of Sciences of the United States of America, 2009;106(11):4459-4464). For additional information, contact M. Yanagisawa, Japan Science & Technology Agcy, ERATO, Yanagisawa Orphan Receptor Project, Saitama 3220012, Japan. Publisher contact information for the journal Proceedings of the National Academy of Sciences of the United States of America is: National Acad Sciences, 2101 Constitution Avenue NW, Washington, DC 20418, USA. Keywords: Japan, Saitama, Life Sciences, Proteomics, Peptide, Proteins. This article was prepared by Science Letter editors from staff and other reports. Copyright 2009, Science Letter via NewsRx.com.
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