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Prenatal disruption of binocular interactions creates novel lamination in the cat's lateral geniculate nucleus 总被引:1,自引:0,他引:1
The elimination of retinogeniculate afferents from one eye on embryonic day 44 (E44) has pronounced effects on the formation of the cellular laminae in the cat lateral geniculate nucleus (LGN). Only two laminae form: a dorsal, "magnocellular" layer, and a ventral, "parvocellular" layer. Soma size measurements and previously reported patterns of termination of retinogeniculate axons suggest that the dorsal lamina is a coalescence of the normal A-laminae and the dorsal, magnocellular division of layer C, while the ventral layer is a composite of the parvocellular sublamina of layer C and the remaining C-laminae. This is a novel pattern of lamination in the LGN that differs from that found in the normal nucleus, not only in that there are now only two cell layers rather than the normal five, but also in that the interlaminar zone occurs in an abnormal location. This result is markedly different from that observed in other species where interlaminar zones present after early monocular enucleation are a subset of the ones which would normally be present. We suggest that, in the absence of ongoing binocular interactions, interactions between functionally distinct retinal ganglion cell classes from the remaining eye may direct the formation of cell laminae in the LGN, even when such interactions are not normally operative. 相似文献
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Neulen J; Raczek S; Pogorzelski M; Grunwald K; Yeo TK; Dvorak HF; Weich HA; Breckwoldt M 《Molecular human reproduction》1998,4(3):203-206
Vascularization is a prominent event during corpus luteum formation,
providing low density lipoproteins for steroid biosynthesis and enabling
transport of secreted steroids. The process of vascularization is
controlled by specific regulators. Vascular endothelial growth factor
(VEGF), otherwise named vascular permeability factor (VPF), induces
endothelial cell proliferation as well as angiogenesis in vivo and
increases capillary permeability. Here we report the expression of VEGF/VPF
mRNA by cultured human luteinized granulosa cells (GC) for at least 10
days. Without HCG VEGF/VPF expression declined after day 4 and by day 10
was reduced to approximately 30% of the value at day 4. However, after
culture in the presence of 1 U/ml human chorionic gonadotrophin (HCG),
expression of VEGF/VPF mRNA by GC was four times greater than control
experiments by day 10, and increased 100% from day 4 to day 10.
Simultaneously, HCG supplementation increased VEGF/VPF secretion by GC.
Medium VEGF/VPF on day 3 was 13 pM without and 11 pM with HCG. Medium
VEGF/VPF on day 10 was 6 pM without HCG and 29 pM with HCG. These results
suggest that vascularization of the corpus luteum is induced by
HCG-mediated effects of VEGF/VPF.
相似文献
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McKernan RM Rosahl TW Reynolds DS Sur C Wafford KA Atack JR Farrar S Myers J Cook G Ferris P Garrett L Bristow L Marshall G Macaulay A Brown N Howell O Moore KW Carling RW Street LJ Castro JL Ragan CI Dawson GR Whiting PJ 《Nature neuroscience》2000,3(6):587-592
Inhibitory neurotransmission in the brain is largely mediated by GABA(A) receptors. Potentiation of GABA receptor activation through an allosteric benzodiazepine (BZ) site produces the sedative, anxiolytic, muscle relaxant, anticonvulsant and cognition-impairing effects of clinically used BZs such as diazepam. We created genetically modified mice (alpha1 H101R) with a diazepam-insensitive alpha1 subtype and a selective BZ site ligand, L-838,417, to explore GABA(A) receptor subtypes mediating specific physiological effects. These two complimentary approaches revealed that the alpha1 subtype mediated the sedative, but not the anxiolytic effects of benzodiazepines. This finding suggests ways to improve anxiolytics and to develop drugs for other neurological disorders based on their specificity for GABA(A) receptor subtypes in distinct neuronal circuits. 相似文献