9 research outputs found
Desperately Seeking Supersymmetry [SUSY]
In this article we try to clarify why supersymmetry [SUSY] and supersymmetric
grand unified theories [SUSY GUTs] are the new standard model of particle
physics, i.e. the standard by which all other theories and experiments are
measured.Comment: 69 pages, 15 figures, new references adde
ATP-Evoked Intracellular Ca Signaling of Different Supporting Cells in the Hearing Mouse Hemicochlea
Hearing and its protection is regulated by ATP-evoked Ca2+ signaling in the supporting cells of the organ of Corti, however, the unique anatomy of the cochlea hampers observing these mechanisms. For the first time, we have performed functional ratiometric Ca2+ imaging (fura-2) in three different supporting cell types in the hemicochlea preparation of hearing mice to measure purinergic receptor-mediated Ca2+ signaling in pillar, Deiters' and Hensen's cells. Their resting [Ca2+]i was determined and compared in the same type of preparation. ATP evoked reversible, repeatable and dose-dependent Ca2+ transients in all three cell types, showing desensitization. Inhibiting the Ca2+ signaling of the ionotropic P2X (omission of extracellular Ca2+) and metabotropic P2Y purinergic receptors (depletion of intracellular Ca2+ stores) revealed the involvement of both receptor types. Detection of P2X2,3,4,6,7 and P2Y1,2,6,12,14 receptor mRNAs by RT-PCR supported this finding and antagonism by PPADS suggested different functional purinergic receptor population in pillar versus Deiters' and Hensen's cells. The sum of the extra- and intracellular Ca2+-dependent components of the response was about equal with the control ATP response (linear additivity) in pillar cells, and showed supralinearity in Deiters' and Hensen's cells. Calcium-induced calcium release might explain this synergistic interaction. The more pronounced Ca2+ leak from the endoplasmic reticulum in Deiters' and Hensen's cells, unmasked by cyclopiazonic acid, may also suggests the higher activity of the internal stores in Ca2+ signaling in these cells. Differences in Ca2+ homeostasis and ATP-induced Ca2+ signaling might reflect the distinct roles these cells play in cochlear function and pathophysiology
The role of N-methyl-D-aspartate receptors and nitric oxide in cochlear dopamine release
Dopamine (DA) released from lateral olivocochlear (LOC) terminals may have a neuroprotective effect in the cochlea. To explore the role of N-methyl-D-aspartate (NMDA) receptors and nitric oxide (NO) in the modulation of a cochlear DA release, we measured the release of [(3)H]DA from isolated mouse cochlea in response to the application of NMDA. NMDA at 100 mu M significantly increased the electrical-field stimulation-evoked and resting release of DA from the cochlea. The NO donor sodium nitroprusside enhanced the basal outflow of DA but failed to influence the evoked release. The administration of the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) alone was ineffective, but it significantly inhibited the initial phase of the NMDA-induced elevation of DA outflow, which suggested the role of NO in the NMDA-induced DA release. The DA uptake inhibitor nomifensine increased the electrically evoked release of DA. Nomifensine failed to change the effect of NMDA on the resting or electrically-evoked DA release, which suggested that the uptake mechanism does not play a role in NMDA-evoked and NO-mediated DA release. In summary, we provide evidence that NO can modulate the release of DA from the cochlea following NMDA receptor activation, but does not affect the uptake of DA. (C) 2008 IBRO. Published by Elsevier Ltd. All rights reserved
Gastric teratoma in infancy and childhood: Report of three cases and review of literature
Dopaminergic Modulation of the Voltage-Gated Sodium Current in the Cochlear Afferent Neurons of the Rat
The Elusive Muse : Understanding Musical Giftedness
Many labels exist to outline musical giftednessor aspects of it; a profusion resulting from differentepistemological positions, disagreements, and theconsiderable complexity of the issue. In this chapter,musical giftedness as a sub-cultural attribute is discussedas well as the problems inherent in attributionby consensus procedures. Based on available researcha conceptual model of musical giftedness is outlinedbased on domain generality and domain specificity,thus proposing an understanding of musical giftednessas a set of core skills and sets of key skills, particularfor specific domains. The question of heredity isbrought to the fore as is the significance of accumulatedpractice over time. Differences between the developmentof Western Classical musicians and popularmusicians are demonstrated. Recent research on giftednessidentification is also discussed followed by aconcluding overview of potential research pitfalls asthe understanding of musical giftedness continues tobe explored