| Optic tectum of mesencephalon is a very important part in optical information pathway,being obvious delaminate structure when it is stained. The morphological character and developmental rule of stratum griseum centrale(SGC) within chick optic tectum in different embryonic days, the cytoarchitecture and morphology of neurons that projecting to nucleus rotundus in chick SGC were observed and analysed using Nissl staining, and Fast blue nerve labeling combined with intracellular injection of Lucifer Yellow(LY) technique to furtherly understand formation mechanism of visual and optical information pathway in chick. SGC neurons were retrogradely labeled by injecting a small amount of Fast blue(FB) into Rt. After 84 hours the chicks were perfused with fixative and the midbrains were sectioned with vibratome into 300 μm slices. Lucifer yellow(LY) was injected into FB labeled SGC neurons by micro electrophoresis under fluorescence microscopy. And had a preliminary exploration of intracellular injection of lucifer yellow technique, provide a reference for further study on optical information pathway in chick. The results showed that the average thickness of SGC, its thickness proportion in whole layer of tectum are not the same in different developmental periods of embryo. In the E11, E14, E17 and E20 embryo days, the average thickness of SGC is(132.95±14.80) μ m,(150.38±37.83) μ m,(167.88±10.05) μ m, and(171.09±31.98) μ m(mean ± SD, n=40) respectively. Their thickness proportions in whole layer of tectum is 24.23%, 26.88%, 28.92%, and 29.42% respectively. It indicated that the developmental speed of SGC in the initial period is rapid, late slow. Lucifer yellow was injected into FB labeled SGC neurons, the soma of the cells appeared triangular, oval, polygonal or spindle, of which the most common is triangle. The area of SGC neurons,dendrite fields, long diameter, and short diameter is(336.91±70.81) μm2,(121.27±49.54) μ m,(29.38±6.44) μ m and(14.20±1.65) μ m respectively. Long diameter of SGC neurons was analysed according to the prescribing of large, middle and small cells. The large cells, whose long diameter are more than 30 μm, occupy 46.03%(n=29). The middle cells, whose long diameter are more 20-30 μm, occupy46.03%(n=29). The small cells, whose long diameter are less than 20 μm, occupy 7.94%(n=5). The main of the SGC cells were large and medium ones. According to the size of dendrite fields, they were divide into narrow dendrite field, middle dendrite field, and wide dendrite field. The narrow ones, being less than 90 μm, occupy 25.40%(n=16). The middle ones, being 90-150 μm, occupy 44.44%(n=28). The wide ones, being larger than 150 μm, occupy 30.16%(n=19)(mean ± SD, n=63). The mean area of type 1 neurons, whose somata were located in superficial part of the SGC, gave off dendritic endings to layer F, is(262.2±72.4) μm2(n=22). The mean area of type 2 neurons, whose somata were also located in superficial part of the SGC, gave off dendritic endings to layer D, is(321.7±157.9)μm2(n=19). The mean area of type 3 neurons, whose somatawere located in deep partof the SGC, gave off primary dendrites obliquely in layer H-J of SGFS, is(408.20±180.13) μm2(n=13). The average area of type 4 neurons, whose cell bodies were located in the shallow part of the SGC, It exudes dendritic levels and their dendrites were located in the SGC, is(363.52±118.23)μm2(n=9). The dendrite fields of type 1 neurons is(277.79±133.6)μm(n=20), the dendrite fields of type 2 neurons is(236.07±113.2) μm(n=21), the dendrite fields of type 3 neurons is(195.49±90.3) μm(n=14), the dendrite fields of type 4 neurons is(148.86±110.2) μm(n=8). Intracellular filling can Labeled integrative SGC soma and neurites that project to Rt. Contrasting to other labeling methods, the LY intracellular filling method has the advantages of being able to label a single neuron, avoiding the interferer by the fibers of other neurons. It is a good method to study the projection between neurons and the morphology of the original cells. Key words: Chick; Stratum Griseum Centrale(SGC);Fast Blue(FB); Lucifer Yellow... |
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