ISSN:0736-5748    

DOI:10.1016/0736-5748(94)90060-4

出版商:Wiley    

年代:2003

数据来源: WILEY

ISSN:0736-5748    

DOI:10.1016/0736-5748(94)90061-2

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThe non‐competitiveN‐methyl‐d‐aspartate antagonistcis‐Pip/Me 1‐[1‐(2‐thienyl)‐2‐methyl‐cyclohexyl] piperidine (GK11) either in racemic(±) or (−) enantiomeric form has been investigated on survival of human fetal spinal cord cells in culture. The treated cultured cells were processed for immunocytochemical detection of GABA at different time intervals ranging from 3 to 27 weeks. The number of GABA‐stained cells was found to be greater in the treated cultures than in the control ones. The qualitative and quantitative morphological features of both control and treated cells were analysed by computer‐assisted methods which allowed us to individualize three different populations: (1) all control and treated small neuritic field neurons, (2) young control and old treated large neuritic field neurons and (3) old control neurons with large neuritic fields.

ISSN:0736-5748    

DOI:10.1016/0736-5748(94)90062-0

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractChanges in metabolic activity in the hyperstriatal regions of the chick forebrain have been assessed just prior to and after hatching using14C2‐deoxyglucose (2‐DG) autoradiography. Embryos were injected on day E19, followed by either exposure to light for 30 min or being held in darkness. Other embryos were injected on day E20, after pipping of the egg shell had occurred, and chicks were injected on day 1 (D1) after hatching, followed by light exposure. In the E19 groups metabolic activity in visual regions of the hyperstriatum accessorium (HA) was significantly higher than that in the hyperstriatum dorsale (HD), the region which receives the thalamofugal visual projections. The result was the same in both the light and dark exposed embryos, indicating that the high level of activity in HA on day E19 is not visually driven and that HA may be processing inputs from other sensory modalities. At stage E20 the activities of HA and HD did not differ and by day 1 post‐hatching HD activity exceeded that of HA. Activity in HA fell between E19 and E20, while in HD activity rose between E20 and D1. The developmental sequence of metabolic activity levels in the intermediate medial hyperstriatum ventrale (IMHV), a region involved with imprinting memory formation, was higher on E19 and D1 than on E20. E20 is thus a quiescent period of neural activity in the hyperstriatum prior to hatching. Although a small number of the embryos showed distinct hemispheric asymmetries in metabolic activity, overall there was no significant asymmetry in the embryo groups. The implications of these results for imprinting and early perceptual processing are discussed: it appears that HA activity may be inhibited or limited during the sensitive period for visual imprinting, thereby temporarily diminishing the importance of the thalamofugal visual pathway relative to the tectofugal pathway in the imprinting process.

ISSN:0736-5748    

DOI:10.1016/0736-5748(94)90063-9

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractPrevious studies have shown that extracts from the target optic tectum stimulate neurite outgrowth from retinal explants. The present study indicates that the choroid coat is an even richer source of retinotrophic activity. We thus studied the effects of recombinant rat ciliary neurotrophic factor (CNTF) on primary cultures of dissociated chick ciliary ganglion neurons and retinal explants for a comparison with choroid coat extract from the E 18 chick. For our assays, E9 ciliary neurons were incubated in collagen gels and retinal explants were cultured on collagen gels with the addition of the trophic factors and maintained for two or four days. Survival of ciliary neurons per area as well as maximal neurite length in retinal cultures were determined. Growth responses occurred in a dose‐dependent manner both to CNTF and choroid extract. Immunofluorescence examination of cells and developing processes showed 200 kdal neurofilament positivity demonstrating that the cells studied were neurons with neurites. It is concluded that a trophic activity of the choroid as well as the recombinant CNTF stimulate retinal neuron survival and neurite extension. The results suggest that CNTF may have developmental functions in the establishment of the visual pathways.

ISSN:0736-5748    

DOI:10.1016/0736-5748(94)90064-7

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThe sensory nerves, containing substance P and calcitonin gene‐related peptide, and noradrenaline‐containing sympathetic nerves of the rat uterus were analyzed following long‐term sympathectomy with guanethidine in prepubertal (four weeks), young adult (eight weeks) and fully adult animals (18 weeks). Immunohistochemical and histochemical methods were used in association with nerve density measurements and biochemical assays. The main findings were as follows: (1) long‐term guanethidine treatment completely abolished the noradrenergic innervation of the uterine horn and parametrial tissue and markedly reduced the tissue levels of noradrenaline in both regions at the three ages analysed; (2) in the uterine hom guanethidine treatment had no effect on the tissue levels of either calcitonin gene‐related peptide or substance P or on the density of calcitonin gene‐related peptide‐containing nerves, at any of the three ages studied; (3) in the parametrial tissue increased levels of calcitonin gene‐related peptide were observed at 8 and 18 weeks of age, together with a significant increase in the density of calcitonin gene‐related peptide‐containing nerves. Substance P levels showed a transient increase in this tissue at eight weeks. In conclusion, long‐term sympathectomy with guanethidine resulted in an increase in calcitonin gene‐related peptide and substance P in sensory nerves in the parametrial tissue, but not in the uterine horn. The changes in the parametrial tissue only occurred after puberty. It is suggested that sensory nerves in the uterine horn may be less responsive to sympathetic denervation since loss of sympathetic nerves occurs as part of a normal physiological process during pregnancy in this region.

ISSN:0736-5748    

DOI:10.1016/0736-5748(94)90065-5

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThe investigation of interactions between growing neurites and target cells during the development of the sensible corneal innervation is of crucial importance for understanding certain corneal diseases which are related to abnormal patterns of innervation. The purpose of the present work was to establish a culture system of cornea and trigeminal neurons and to examine interactions between these tissues. The responses of neurons derived from explanted embryonic chick trigeminal ganglia to co‐explanted slices prepared from embryonic cornea were monitored over several days in culture. The growth of trigeminal fibers, but not of neurites derived from control tissues such as trigeminal mesencephalic nucleus or ciliary ganglion, was preferentially directed towards the co‐cultured corneal slices. The ingrowth of trigeminal axons into the cornea was followed by formation of elaborate axonal terminal branches. Individual dissociated trigeminal neurons of pseudo‐unipolar or bipolar classes developed their typical morphologies in culture. In co‐cultures with corneal slices, they reacted to the corneal co‐explant by frequently retracting some branches and forming or elongating other ones, which were predominantly directed towards the target tissue. In addition, the presence of a co‐explanted trigeminal ganglion increased the rate of growth in the dissociated trigeminal neurons. The effect was not additive when cornea was present. Antibodies against nerve growth factor (NGF) and the low‐affinity p75‐NGF receptor (LANGFR) revealed that trigeminal ganglion cells support neuritic growth by secreting NGF, whereas corneal cells secrete additional factor(s) which act via the LANGFR.

ISSN:0736-5748    

DOI:10.1016/0736-5748(94)90066-3

出版商:Wiley    

年代:2003

数据来源: WILEY

ISSN:0736-5748    

DOI:10.1016/0736-5748(94)90067-1

出版商:Wiley    

年代:2003

数据来源: WILEY

ISSN:0736-5748    

DOI:10.1016/0736-5748(94)90068-X

出版商:Wiley    

年代:2003

数据来源: WILEY