摘要:

AbstractEffects of a single injection of either 150 μg human recombinant glial cell line‐derived neurotrophic factor (rGDNF) or vehicle into the right substantia nigra were analyzed in 12 normal adult female rhesus monkeys. The studies included evaluating whole animal behavior, electrochemical recordings of striatal dopamine release, neurochemical determinations of basal ganglia and nigral monoamine levels, and immunohistochemical staining of the nigrostriatal dopamine system. The behavioral effects over the 3–week observation period following trophic factor administration were small, with blinded observers unable to distinguish between GDNF and vehicle‐treated animals. Quantitative measurements did show that five of six trophic factor recipients experienced some weight loss and four of the six GDNF recipients displayed small, but significant, increases in daytime activity levels. In vivo electrochemical recordings in the ipsilateral caudate and putamen 3 weeks after GDNF administration revealed increased potassium‐evoked release of dopamine in trophic factor recipients. In a second series of animals killed at the same time, dopamine levels in the substantia nigra and ventral tegmental area of GDNF recipients were significantly increased, with ipsilateral values more than 200% higher than contralateral and control levels. Levels of the dopamine metabolite HVA were significantly elevated in the substantia nigra, ventral tegmental area, and caudate nucleus ipsilateral to the trophic factor injection. There was a trend toward increased HVA levels in the ipsilateral putamen, nucleus accumbens, and globus pallidus in GDNF‐treated animals, but the ratios of HVA to dopamine were not significantly different between vehicle‐ and GDNF‐treated recipients. Although some tissue damage from the delivery of concentrated trophic factor was evident, dopamine neurons remained in and adjacent to the injection site. In the substantia nigra ipsilateral to GDNF administration, dopamine‐neuron perikaryal size was significantly increased, along with a significant increase in tyrosine hydroxylase‐positive axons and dendrites. We conclude that, in the adult rhesus monkey, a single intranigral GDNF injection induces a significant upregulation of mesencephalic dopamine neurons which lasts for weeks. © 1

ISSN:0092-7317    

DOI:10.1002/cne.903630302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe development of the retinal pigment epithelium (RPE) was studied in rhesus monkey (Macaca mulatta) fetuses, neonates, and juveniles exposed to a pulse of (3H‐TdR) between embryonic day (E) 25 and postnatal day (P) 204 and examined at short and long intervals after the injection of the isotope.The RPE develops from the outer layer of the optic cup which by E45 consists of a multistratified epithelium. The outer layer appears immature near the retina's edge and gradually becomes monostratified and more mature centrally. Even at this early stage, all cells contain pigmented melanosomes, although peripherally the pigment is limited to the apical portion of the cells. Examination of autoradiograms from animals allowed to survive for several postnatal months shows that monkey RPE cell genesis begins just after E27, increasing to a peak frequency of 0. 38 cells/mm at E43. Between E30 and E85 the density of radiolabelled cells varies within a restricted range of from 0.2 to 0.4 cells/mm (mean = 0.25 ± 0.09). From the density of radiolabelled cells, and data on the overall density of RPE cells in the juvenile retina, we determined the labelling index. During the first half of gestation, between 0. 38% and 0. 99% (mean = 0. 65 ± 0. 22) of RPE cells are generated during the short interval of isotope availability after pulse injection. Approximately 5% of RPE cells were generated by E33, and 50% by E71. After E85, RPE cytogenesis begins gradually to decrease, and 95% of the cells have been generated by the time of birth. Continued, very low density (0. 01 cells/mm) cytogenesis in the RPE is seen at P17, and persists at least until seven months postnatally.RPE cell genesis begin near the fovea, and proceeds towards the periphery. Cell division largely ceases in both foveal and perifoveal regions by E56, at which time labelled cells first begin to appear peripheral to the equator. Besides the timing differences, RPE genesis in the central retina differs from that in the peripheral retina in that it proceeds at a higher rate, and lasts for a shorter time period. A prolonged postnatal period of low density RPE cell genesis persists in both central and peripheral retina. Comparison of the pattern of expansion of the area containing radiolabelled cells in the RPE and neuroretina demonstrates a remarkable spatial and temporal correspondence. Close analysis suggests that at any point on the retina, the last cells are generated in the neuroretina slightly before the last cells in the RPE. © 1995 Wiley‐Lis

ISSN:0092-7317    

DOI:10.1002/cne.903630303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractAlthough central neurons do not naturally recover following injury, damaged adult septal neurons can regenerate when nerve growth factor (NGF) is provided along with a suitable cellular substrate. This study investigates the outgrowth of axotomized septal neurons grafted with primary fibroblasts genetically modified to produce NGF. Confocal microscope images of double staining for neuritic markers (neurofliament or low‐affinity NGF receptor) and the astrocytic marker glial fibrillary acidic protein (GFAP) demonstrated that regenerating neurites crossed dense buildups of astrocytic processes at the edges of NGF‐producing grafts and were in apposition with astrocytic processes within NGF‐producing grafts. Immunoreactivity for acetylcholinesterase and low‐(p75) and high‐affinity (TrkA) NGF receptors was dense in NGF‐producing grafts but absent in control grafts. NGF‐grafted rats exhibited significantly increased hippocampal density of p75‐immunoreactive fibers and significantly decreased ectopic hippocamoal sympathetic ingrowth as compared to control‐grafted rats. Rats with unilateral fimbria‐fornix lesions and NGF‐producing grafts exhibited ameliorated performance on a simple memory task. These findings demonstrate that implantation of NGFproducing grafts to the lesion cavity allows axotomized septal cholinergic neurons to reinnervate the hippocampus, and that rats receiving these grafts show a partial recovery of function.

ISSN:0092-7317    

DOI:10.1002/cne.903630304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractTo test the hypothesis that embryonic brain cells utilize a creatine phosphate energy shuttle, we examined the pattern of creatine kinase (CK) isoform expression and localization in the fetal rat brain. Moderate levels of CK activity are present at embryonic day 14 (7 U/mg protein) and decrease slightly until 3 days postpartum followed by a rapid, fourfold up‐ regulation to adult levels by 1 month (18 U/mg protein). In parallel with changes in enzyme activity, there is a biphasic and coordinate pattern of expression of brain‐type CK (BCK) and ubiquitous mitochondrial CK (uMtCK) determined by nondenaturing electrophoresis and immunoblot analysis. The localization of CK isoforms was examined by immunocytochemistry, and, during the fetal period, BCK and uMtCK immunoreactivity was detected throughout the central and peripheral nervous system, especially in neuroepithelial regions of the cerebral vesicles and spinal cord. In large cells within the olfactory neuroepithelium and ventral spinal cord, differential compartmentation of CK isoforms was evident, with BCK localized primarily in cell nuclei, whereas uMtCK immunoreactivity was present in the cell body (but not within nuclei). In olfactory bulb neuroepithelium, both isoforms were expressed in the middle zone of the germinal layer associated with DNA synthesis. In embryonic skeletal and cardiac muscle, which also express BCK, the same compartmentation of BCK was seen, with BCK localized primarily in the cell nucleus of cardiac and skeletal myoblasts. These results demonstrate a coordinate pattern of expression and compartmentation of BCK and uMtCK isoforms in the fetal brain that, in some cells, provides the anatomic basis for a nuclear energy shuttle. © 1995 Wiley‐Lis

ISSN:0092-7317    

DOI:10.1002/cne.903630305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe present study used anterograde and retrograde tract tracing and immunohistochemistry to determine the efferent projections of corticotropin‐releasing hormone (CRH) neurons of Barrington's nucleus in the rat. Injections ofPhaseolus vulgaris‐leucoagglutinin into Barrington's nucleus resulted in anterograde labeling in the dorsal motor nucleus of the vagus, periaqueductal gray, medial thalamic nuclei, lateral hypothalamus, paraventricular nucleus of the hypothalamus, lateral preoptic area, and lateral septum. The retrograde tract tracer, fluorogold, injected into the lumbosacral spinal cord labeled many, but not all, CRH‐immunoreactive neurons in Barrington's nucleus. Moreover, some Barrington's neurons that were retrogradely labeled from the spinal cord were not CRH‐immunoreactive. Several CRH‐immunoreactive Barrington's neurons were retrogradely labeled by fluorogold injections into the periaqueductal gray, and these were located predominantly in the dorsal part of the nucleus. Additionally, some CRH‐immunoreactive Barrington's neurons were retrogradely labeled from fluorogold injections into the dorsal motor nucleus of the vagus. In contrast, fluorogold injections into the lateral hypothalamus, lateral preoptic area, or lateral septum did not result in double labeling of CRH‐immunoreactive neurons in Barrington's nucleus. These results suggest that many, but not all, CRH‐containing neurons of Barrington's nucleus project to the lumbosacral spinal cord. In addition to their previously documented projections to the spinal cord, these neurons may be a source of CRH in the periaqueductal gray and dorsal motor nucleus of the vagus. CRH projections of Barrington's nucleus may play a role in behavioral or autonomic aspects of stress responses, in addition to their proposed role in micturition. © 1995

ISSN:0092-7317    

DOI:10.1002/cne.903630306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractPhysiological and anatomical studies have suggested that the endogenous opioid peptide, methionine‐enkephalin (ENK), may directly modulate noradrenergic neurons. Additionally, chronic opiate administration has been shown to increase the levels of a number of G‐proteins and phosphoproteins including the catecholamine synthesizing enzyme, tyrosine hydroxylase (TH). We combined immunogold‐silver localization of tyrosine hydroxylase and immunoperoxidase labeling for ENK in single sections through the nucleus locus coeruleus (LC) in the rostral pons to determine potential substrates for the divergent actions of this opioid peptide. Light microscopic analysis of ENK immunoreactivity in the LC area indicated that ENK fibers are dense and highly varicose. In coronal sections, ENK‐immunoreactive processes were punctate and appeared to envelop LC cell bodies. More rostrally, in the region of catecholamine immunoreactive extranuclear dendrites, ENK‐immunoreactive varicose processes were inter digitated with TH‐labeled processes. Electron microscopy of this rostral region revealed that ENK‐immunoreactive axon terminals contained small clear as well as large dense core vesicles. The large dense core vesicles (1‐10/terminal) were consistently the most immunoreactive and were identified toward the periphery of the axon terminal distal to the active zone of the synapse. Unlabeled axon terminals and glial processes were the most commonly observed elements located adjacent to the plasmalemma of axons containing the labeled dense core vesicles. Axon terminals containing ENK immunoreactivity varied in size (0.3 μm to 2.0 μm) as well as formation of synaptic specializations (i. e., asymmetric versus symmetric). The ENK labeled terminals formed synapses with dendrites with and without detectable TH immunoreactivity. These results provide the first direct ultrastructural evidence that morphologically heterogeneous terminals containing ENK immunoreactivity form synapses with catecholamine dendrites within the LC. The formation of asymmetric and symmetric synaptic specializations suggests that the opioid peptide, ENK, may be colocalized with other neurotransmitters. Furthermore, the distribution of ENK immunoreactivity in axon terminals apposed to other unlabeled afferents or astrocytic processes suggests that actions of ENK may also include presynaptic modulation of other transmitters and/or effects on astrocytes. © 19

ISSN:0092-7317    

DOI:10.1002/cne.903630307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe purpose of this study was to analyze the projections from visually related areas of the cerebral cortex of rhesus monkey to subcortical nuclei involved in eye‐movement control; i. e., the pretectal nuclear complex, the terminal nuclei of the accessory optic system (AOS), and the superior colliculus (SC). The anterograde tracer3H‐leucine was pressure injected bilaterally into the cortex of six monkeys (for a total of 12 cases) involving the primary visual cortex (area 17); the medial prestriate cortex (medial 18/19), dorsomedial area 19; the caudal portion of the cortex of the superior temporal sulcus, upper bank (cytoarchitectural area OAa) and lower bank (area PGa); the lower bank of the caudal lateral intraparietal sulcus (area POa); and the inferior parietal lobule (area 7).The results revealed that the pretectal nucleus of the optic tract received inputs from medial prestriate cortex, dorsomedial part of area 19, OAa, and PGa. The posterior pretectal nucleus received sparse projections from area 7 and the cortex lining the intraparietal sulcus (dorsomedial part of area 19 and POa). The pretectal olivary nucleus was targeted by neurons in cortex of dorsomedial arec 19, and the anterior pretectal nucleus was targeted by neurons in both dorsomedial 19 and area 7.The nuclei of the AOS (dorsal terminal; lateral terminal; and interstitial nuclei of the superior fasciculus, posterior and medial fibers) received projections exclusively from areas OAa and PGa. Furthermore, in one case with PGa injection, the medial terminal nucleus, dorsal portion, was also labeled.The visual cortical areas studied projected differentially upon the SC laminae. The primary visual area 17 projected only to the superficial laminae, i. e., stratum zonale (SZ), stratum griseum superficiale (SGS), and stratum opticum (SO). On the other hand, the medial portion of the prestriate cortex and caudal OAa and PGa targeted the superficial and intermediate laminae, i. e., SZ, SGS, SO, stratum griseum intermediale (SGI), whereas caudal area POa projected primarily to the intermediate layer SGI. Rostral area 7 (mainly 7b) neurons terminated in the stratum album intermediale (SAI); no SC terminals were found in a case in which caudal area 7 (mainly 7a) was injected. © 1995 Wiley‐Lis

ISSN:0092-7317    

DOI:10.1002/cne.903630308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA double immunocytochemical procedure, with two different chromogens, was used to compare the respective distributions of estrogen receptor‐immunoreactive cells and gonadotrophin‐releasing hormone‐immunoreactive neurons on the same sections of the brains of adult male and female rainbow trout (Oncorhynchus mykiss). Estrogen receptor‐immunoreactive cells were observed in the ventral and lateral telencephalon, the preoptic region, the mediobasal hypothalamus, and the ventromedial thalamic nucleus. Gonadotrophin‐releasing hormone immunoreactive perikarya were detected in the olfactory bulbs, the ventral telencephalon, the preoptic area, and the mediobasal hypothalamus. Double‐staining studies showed that, although some estrogen receptor‐positive cells were in close proximity to gonadotrophin releasing hormone‐immunoreactive perikarya, careful examination of 550 gonadotrophinreleasing hormone‐positive cells from five adult females and two adult males failed to demonstrate any evidence that gonadotrophin‐releasing hormone neurons coexpress estrogen receptor in the brain of the rainbow trout.The present study provides, for the first time in teleosts, morphological evidence that gonadotrophin‐releasing hormone neurons do not represent major direct targets for estradiol, suggesting that the positive feedback effects of estradiol onto the gonadotrophin‐releasing hormone system are likely to be conveyed via other cell populations.

ISSN:0092-7317    

DOI:10.1002/cne.903630309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractAllatostatins isolated from the cockroachDiploptera punctataare a family of neuropeptides that inhibit juvenile hormone synthesis in cockroaches and related insects but not in flies. In cockroaches, these widely distributed peptides have been shown to have other functions. This report provides evidence for the presence of allatostatin‐like peptides inDrosophila melanogasterby demonstration of allatostatic activity of extracts of central nervous system from larvae and adults on corpora allata ofDiplopteraand by immunocytochemical localization of peptides inDrosophilawith monoclonal antibody againstDiplopteraallatostatin I. Extract of adult central nervous system showed four times more allatostatic activity than that of the larva or twice the activity per unit volume of central nervous system. This is reflected in an increase in number and arborization of immunoreactive neurons in the adult. The immunoreactive neurons in the central nervous system appear to be interneurons, with the exception of motoneurons in the last abdominal neuromere that project to muscles of the hindgut, a pair of peripheral cells in each of two thoracic segments in the larva and on nerves to wings and halteres in the adult, and endocrine cells of the midgut epithelium. Nerves to the corpus allatum were not immunoreactive. The presence ofDiplopteraallatostatin‐like peptides in interneurons and motoneurons, in the neurohemal networks, and in endocrine cells of the midgut and their absence in nerves to the corpus allatum inDrosophilasuggests that these peptides may function as neuromodulators, myomodulators, and neurohormones and not as regulators of the corpus allatum. © 1995 Wiley‐Lis

ISSN:0092-7317    

DOI:10.1002/cne.903630310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe present study utilises the capacity of wheat germ agglutinin‐conjugated horseradish peroxidase to label both afferent and efferent projections from selected regions of the thalamic reticular nucleus (TRN) to the pulvinar lateralis‐posterior complex (Pul‐LP) of the cat. Fourteen injections into the TRN located between anterior‐posterior levels 8.5 and 4.5 were analysed. The projection of the TEN to the Pul‐LP complex is roughly organised in a topographic manner and is not widespread within the thalamus. Anterograde labelling in the Pul‐LP extended rostrocaudally with a slight oblique dorsoventral orientation. Projections to the medial LP were predominantly but not exclusively from rostral areas of TRN, while projections to the lateral LP were largely from caudal areas of the TRN. Projections to other areas of the Pul‐LP were sparse. The connections between TRN and Pul‐LP were reciprocal, although the distribution of labelled cells and anterograde labelling was not completely overlapping. Reciprocal connections with the dorsal lateral geniculate nucleus were largely with the C‐laminae and the medial interlaminar nucleus. The results are discussed with reference to the corticothalamic projections and the visuotopy of the Pul‐LP. ©

ISSN:0092-7317    

DOI:10.1002/cne.903630311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY