Expression and Localization of CLC Chloride Transport Proteins in the Avian Retina

Members of the ubiquitously expressed CLC protein family of chloride channels and transporters play important roles in regulating cellular chloride and pH. The CLCs that function as Cl−/H+ antiporters, ClCs 3–7, are essential in particular for the acidification of endosomal compartments and protein degradation. These proteins are broadly expressed in the nervous system, and mutations that disrupt their expression are responsible for several human genetic diseases. Furthermore, knock-out of ClC3 and ClC7 in the mouse result in the degeneration of the hippocampus and the retina. Despite this evidence of their importance in retinal function, the expression patterns of different CLC transporters in different retinal cell types are as yet undescribed. Previous work in our lab has shown that in chicken amacrine cells, internal Cl− can be dynamic. To determine whether CLCs have the potential to participate, we used PCR and immunohistochemical techniques to examine CLC transporter expression in the chicken retina. We observed a high level of variation in the retinal expression levels and patterns among the different CLC proteins examined. These findings, which represent the first systematic investigation of CLC transporter expression in the retina, support diverse functions for the different CLCs in this tissue

Preliminary spatiotemporal analysis of the association between socio-environmental factors and suicide

<p>Abstract</p> <p>Background</p> <p>The seasonality of suicide has long been recognised. However, little is known about the relative importance of socio-environmental factors in the occurrence of suicide in different geographical areas. This study examined the association of climate, socioeconomic and demographic factors with suicide in Queensland, Australia, using a spatiotemporal approach.</p> <p>Methods</p> <p>Seasonal data on suicide, demographic variables and socioeconomic indexes for areas in each Local Government Area (LGA) between 1999 and 2003 were acquired from the Australian Bureau of Statistics. Climate data were supplied by the Australian Bureau of Meteorology. A multivariable generalized estimating equation model was used to examine the impact of socio-environmental factors on suicide.</p> <p>Results</p> <p>The preliminary data analyses show that far north Queensland had the highest suicide incidence (e.g., Cook and Mornington Shires), while the south-western areas had the lowest incidence (e.g., Barcoo and Bauhinia Shires) in all the seasons. Maximum temperature, unemployment rate, the proportion of Indigenous population and the proportion of population with low individual income were statistically significantly and positively associated with suicide. There were weaker but not significant associations for other variables.</p> <p>Conclusion</p> <p>Maximum temperature, the proportion of Indigenous population and unemployment rate appeared to be major determinants of suicide at a LGA level in Queensland.</p

Introduction: Human ecology in the Himalaya

Knowledge of human adaptation in the Himalayas has developed more slowly than that for other world mountain systems. At the same time, the opening of the region to research has focused attention toward description in a “natural history” mode until quite recently. Where these studies have addressed issues of adaptation they have tended to do so more as a heuristic tool rather than in terms of contributing to the development of adaptive perspectives from a uniquely Himalayan vantage point. The contributions to this special issue suggest some of Himalayan cultural ecology's new themes as it more directly assumes a truly processual approach that incorporates the individual and domestic dimensions of adaptation within historical and social contexts .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44482/1/10745_2004_Article_BF00889710.pd

Metabotropic glutamate receptor 5 and calcium signaling in retinal amacrine cells

To begin to understand the modulatory role of glutamate in the inner retina, we examined the mechanisms underlying metabotropic glutamate receptor 5 (mGluR5)-dependent Ca2+ elevations in cultured GABAergic amacrine cells. A partial sequence of chicken retinal mGluR5 encompassing intracellular loops 2 and 3 suggests that it can couple to both Gq and Gs. Selective activation of mGluR5 stimulated Ca2+ elevations that varied in waveform from cell to cell. Experiments using high external K+ revealed that the mGluR5-dependent Ca2+ elevations are distinctive in amplitude and time course from those engendered by depolarization. Experiments with a Ca2+-free external solution demonstrated that the variability in the time course of mGluR5-dependent Ca2+ elevations is largely due to the influx of extracellular Ca2+. The sensitivity of the initial phase of the Ca2+ elevation to thapsigargin indicates that this phase of the response is due to the release of Ca2+ from the endoplasmic reticulum. Pharmacological evidence indicates that mGluR5-mediated Ca2+ elevations are dependent upon the activation of phospholipase C. We rule out a role for L-type Ca2+ channels and cAMP-gated channels as pathways for Ca2+ entry, but provide evidence of transient receptor potential (TRP) channel-like immunoreactivity, suggesting that Ca2+ influx may occur through TRP channels. These results indicate that GABAergic amacrine cells express an avian version of mGluR5 that is linked to phospholipase C-dependent Ca2+ release and Ca2+ influx, possibly through TRP channels