Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The reciprocal connections between the claustrum and the auditory cortical fields AI, AII and Ep were investigated by means of Nauta and Fink-Heimer selective silver impregnation procedures, electron microscopic identification of degenerated axons and synaptic boutons, and with the Mesulam horseradish peroxidase retrograde tracing technique. The course and termination of degenerating corticoclaustral axons were investigated following circumscript lesions of the AI, AII and Ep areas in 19 cats. The greatest amount of degeneration debris was observed following destruction of the AII area. The central third of the claustrum (stereotaxic level A13-A15) is filled with degenerating terminals (d. t.), with greatest concentration in the lateral wedge of the nucleus, and along its inferolateral border. Rostrally and caudally the density of degeneration diminishes but scattered d. t. were observed up to the rostral pole, and a moderate number - up to the caudal pole of the claustrum. Slightly lesser amount of d. t. was observed following Ep destruction. The caudal portion of the claustrum is filled with d. t. In the central third the degeneration field occupies mainly the ventrolateral zone of the nucleus. The rostral pole of the claustrum is free of degeneration. The projection from the AI field is considerably more moderate, and is diffusely organized. A substantial number of d. t. is encountered only in the lateral parts of the central claustral third. The crossed corticoclaustral connections mirror the ipsilateral ones but are far more modest. The AII area projects mainly to the central claustral third, the Ep area--to the caudal third. The projection of the AI area to the contralateral claustrum is very weak. The electron microscopic examination of the claustrum following auditory cortex destruction in 9 cats revealed an appreciable number of degenerating synaptic boutons. They undergo dark and more rarely light degenerative changes. The cortical terminals are classified in two types: "small round" (SR), comprising approximately 70 to 75% of the corticoclaustral boutons, and "large round" (LR)-25-30%, resp. The SR boutons measure 0.6-1.2 micron, contain tightly packed round synaptic vesicles (380-420 A), and form asymmetrical axodendritic contacts. The LR boutons measure 1-2.5 microns, contain round vesicles (400-500 A) and form asymmetrical axodendritic and (far more rarely) axosomatic contacts. The claustrocortical connection was investigated in 13 cats with selective injections of 30% HRP in the three subdivisions of the auditory cortex.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Reciprocal connections between the claustrum and the auditory cortical fields in the cat. An experimental study using light- and electron microscopic anterograde degeneration methods, and the horseradish peroxidase retrograde axonal transport. 341 13

The AII amacrine cell is a critical interneuron in the rod pathway of the mammalian retina. Rod signals pass into cone pathways by means of gap junctions between AII amacrine cells and ON cone bipolar cells. Filling AII amacrine cells with Neurobiotin produces labeling of cone bipolar cells by means of these gap junctions. However, tracer injections into bipolar cells do not produce labeling of the AII network (Vaney [1997] Invest Ophthalmol Vis Sci. 38:267-273), which suggests that the AII/bipolar gap junctions allow the passage of tracer in only one direction. This mechanism stands in contrast to physiological results, which indicate that light adapted signals can pass from ON cone bipolar cells into the AII network (Xin and Bloomfield [1999] Vis Neurosci. 16:653-665). Here, we report that a variety of ON and OFF bipolar cells are sometimes anomalously coupled to the A-type horizontal cell network. These relatively rare examples do not result from dye injection errors, but seem to represent minor developmental errors. However, this provides a method to obtain Neurobiotin-filled cone bipolar cells without the necessity of impaling them with a microelectrode. Under these conditions, Neurobiotin spreads from ON cone bipolar cells into neighboring AII amacrine cells. The dye-coupled AII amacrine cells, positively identified by double labeling with an antibody against calretinin, were centered around anomalously coupled ON bipolar cells. These results indicate that AII/bipolar cell gap junctions allow tracer coupling in both directions, consistent with previous physiological results. The previous failure to detect the passage of neuronal tracer from injected bipolar cells to AII amacrine cells may reflect electrode damage or perhaps the asymmetrical voltage sensitivity of a heterotypic gap junction.
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PMID:Coupling from AII amacrine cells to ON cone bipolar cells is bidirectional. 1150 43

Light-evoked excitatory cation current (DeltaI(C)) and inhibitory chloride current (DeltaI(Cl)) of rod and cone depolarizing bipolar cells (DBC(R)s and DBC(C)s) and AII amacrine cells (AIIACs) in dark-adapted mouse retinal slices were studied by whole-cell voltage-clamp recording techniques, and the cell morphology was revealed by Lucifer yellow fluorescence with a confocal microscope. DeltaI(C) of all DBC(R)s exhibited similar high sensitivity to 500 nm light, but two patterns of DeltaI(Cl) were observed in DBC(R)s with slightly different axon morphology. At least two types of DBC(C)s were identified: one with axon terminals ramified in 70-85% of the depth of the inner plexiform layer (IPL) and DBC(R)-like DeltaI(C) sensitivity, whereas the other with axon terminals ramified in 55-75% of IPL depth and much lower DeltaI(C) sensitivity. The relative rod/cone inputs to DBCs and AIIACs were analysed by comparing the DeltaI(C) and DeltaI(Cl) thresholds and dynamic ranges with the corresponding values of rods and cones. On average, the sensitivity of a DBC(R) to the 500 nm light is about 20 times higher than that of a rod. The sensitivity of an AIIAC is more than 1000 times higher than that of a rod, suggesting that AIIAC responses are pooled through a coupled network of about 40 AIIACs. Interactions of rod and cone signals in dark-adapted mouse retina appear asymmetrical: rod signals spread into the cone system more efficiently than cone signals into the rod system. The mouse synaptic circuitry allows small rod signals to be highly amplified, and effectively transmitted to the cone system via rod-cone and AIIAC-DBC(C) coupling.
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PMID:Light-evoked current responses in rod bipolar cells, cone depolarizing bipolar cells and AII amacrine cells in dark-adapted mouse retina. 1518 Nov 69

Light-evoked excitatory cation current (DeltaIC) and inhibitory chloride current (DeltaICl) of rod and cone bipolar cells and AII amacrine cells (AIIACs) were recorded from slices of dark-adapted mouse retinas, and alpha ganglion cells were recorded from flatmounts of dark-adapted mouse retinas. The cell morphology was revealed by Lucifer yellow fluorescence with a confocal microscope. DeltaIC of all rod depolarizing bipolar cells (DBCRs) exhibited similar high sensitivity to 500 nm light, but two patterns of DeltaICl were observed with slightly different axon morphologies. At least two types of cone depolarizing bipolar cells (DBCCs) were identified: one with axon terminals ramified in 70-85% of IPL depth and DBCR-like DeltaIC sensitivity, and the other with axon terminals ramified in 55-75% of IPL depth and much lower DeltaIC sensitivity. The relative rod/cone inputs to DBCs and AIIACs were analyzed by comparing the DeltaIC and DeltaICl thresholds and dynamic ranges with the corresponding values of rods and cones. On average, the sensitivity of a DBCR to the 500 nm light is about 20 times higher than that of a rod. The sensitivity of an AIIAC is more than 1000 times higher than that of a rod, suggesting that AIIAC responses are pooled through a coupled network of about 40 AIIACs. Interactions of rod and cone signals in dark-adapted mouse retinas appear asymmetrical: rod signals spread into the cone system more efficiently than cone signals into the rod system. The mouse synaptic circuitry allows small rod signals to be highly amplified and effectively transmitted to the cone system via rod/cone and AIIAC/DBCC coupling. Three types of alpha ganglion cells (alphaGCs) were identified. (1) ONGCs exhibits no spike activity in darkness, increased spikes in light, sustained inward DeltaIC, sustained outward DeltaICl of varying amplitude, and large soma (20-25 microm in diameter) with an alpha-cell-like dendritic field about 180-350 microm stratifying near 70% of the IPL depth. (2) Transient OFFalphaGCs (tOFFalphaGCs) exhibit no spike activity in darkness, transient increased spikes at light offset, small sustained outward DeltaIC in light, a large transient inward DeltaIC at light offset, a sustained outward DeltaICl, and a morphology similar to the ONalphaGCs except for that their dendrites stratified near 30% of the IPL depth. (3) Sustained OFFalpha GCs (sOFFalphaGCs) exhibit maintained spike activity of 5-10 Hz in darkness, sustained decrease of spikes in light, sustained outward DeltaIC, sustained outward DeltaICl, and a morphology similar to the tOFFalphaGCs. By comparing the response thresholds and dynamic ranges of alphaGCs with those of the pre-ganglion cells, our data suggest that the light responses of each type of alphaGCs are mediated by different sets of bipolar cells and amacrine cells.
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PMID:Synaptic circuitry mediating light-evoked signals in dark-adapted mouse retina. 1553 95