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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Evidence derived from many experimental approaches indicates that cholinergic neurons in the dorsal striatum (caudate-putamen) are responsive to excitatory amino acids. Furthermore, evidence from physiological experiments indicate that the excitatory input is derived from the cortex and/or the thalamus. The object of the present experiment was to anatomically test whether cholinergic neurons receive cortical and/or thalamic input in the dorsal striatum using a combined anteograde tracing and immunocytochemical approach at both the light- and electron-microscopic levels. Rats received injections of the anterograde tracers Phaseolus vulgaris-leucoagglutinin or biocytin at multiple sites in the frontal cortex or parafascicular nucleus of the thalamus. Sections of the striatum were stained to reveal the anterogradely transported markers and then immunostained to reveal choline acetyltransferase immunoreactivity. The striata of these animals contained dense networks of anterogradely labelled fibres that were dispersed throughout the neuropil and interspersed with the choline acetyltransferase-immunoreactive (i.e. cholinergic) perikarya and dendrites. The anterogradely labelled fibres were often closely apposed to the choline acetyltransferase-immunoreactive neurons. Examination of electron-microscopic sections failed to demonstrate cortical terminals in synaptic contact with the cholinergic neurons even when choline acetyltransferase-immunoreactive structures were examined that had first been identified in the light microscope as having cortical terminals closely apposed to them. In these cases it was often observed that the cortical terminal, although apposed to the membrane of the labelled neurone, made synaptic contact with an unlabelled spine that was in the vicinity. In contrast to the cortical input, analysis of material that was double-stained to reveal thalamostriatal terminals and choline acetyltransferase-immunoreactive structures, revealed that the thalamostriatal terminals were often in asymmetrical synaptic contact with the perikarya and dendrites of cholinergic neurons. It is concluded that the cholinergic neurons of the dorsal striatum, like those of the ventral striatum or nucleus accumbens [Meredith and Wouterlood (1990) J. comp. Neurol. 296, 204-221] receive very little or no input from the cortex but are under a prominent synaptic control by the thalamostriatal system. Those pharmacological effects of excitatory amino acids on the cholinergic systems of the striatum are therefore presumably related to the thalamostriatal and not the corticostriatal system.
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PMID:Input from the frontal cortex and the parafascicular nucleus to cholinergic interneurons in the dorsal striatum of the rat. 148 13

Plants survive against myriad environmental odds while remaining rooted to a single spot. The time scale over which plant cells can respond to environmental cues is seldom appreciated. Fluorescent protein-assisted live imaging of peroxisomes reveals that they respond within seconds of exposure to hydrogen peroxide and hydroxyl radicals by producing dynamic extensions called peroxules. Observations of the Arabidopsis flu mutant and treatments with xenobiotics eliciting singlet oxygen and superoxide reactive oxygen species suggest that the observed responses are specific for hydroxyl radicals. Prolonged exposure to hydroxyl radicals inhibits peroxule extension, and instead causes motile and spherical peroxisomes in a cell to become immotile and elongate several-fold. Expression of photo-convertible EosFP-PTS1 demonstrates that vermiform peroxisomes result from rapid stretching of individual peroxisomes, while the subsequent 'beads-on-a-string' morphology results from differential protein distribution within an elongated tubule. Over time, the beads in elongated peroxisomes also extend peroxules randomly before undergoing asynchronous, asymmetrical fission. Peroxule extension does not appear to involve cytoskeletal elements directly, but is closely aligned with and reflects the dynamics of ER tubules. Peroxisomal responses reveal a rapidly invoked subcellular machinery that is involved in recognition of hydroxyl stress thresholds, and its possible remediation locally through extension of peroxules or globally by increasing peroxisome numbers. A matrix protein retro-flow mechanism that supports peroxisome-ER connectivity in plant cells is suggested.
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PMID:Peroxule extension over ER-defined paths constitutes a rapid subcellular response to hydroxyl stress. 1982 Mar 26