摘要:

AbstractThe binding of RPE‐1, a mouse monoclonal antibody selective for newt retinal pigment epithelium, was followed in eyes undergoing embryonic developemnt and retinal regeneration. Using the indirect immunofluorescence technique on frozen sections, we observed bright and continuous labelling exclusively in the retinal pigment epithelium (RPE) of normal adult newts, but labelling became diminished near the ora serrata region and stopped abruptly at the ciliary margin. During development, labelling was not detected in the retinal pigment epithelium (RPE) until the formation of photoreceptor outer segments and was not observed in any other ocular tissue. There was no correlation between the appearance of pigment in retinal pigment epithelial cells and their labelling with the RPE‐1 antibody. Furthermore, albino salamander embryos showed the same pattern of labelling with RPE‐1 as that seen in age‐matched pigmented animals. During retinal regeneration, RPE cells were labelled less intensely, but heavy labelling was observed in the newly formed retinal cells. With time, labelling in regenerated retina receded, so that by the end of regeneration, labelling by RPE‐1 was once more restricted to the RPE cells. The identification of RPE‐1 as a marker for postmitotic retinal neurons about to undergo differentiation provides a promising approach for further studies of regeneration with the help of mole

ISSN:0092-7317    

DOI:10.1002/cne.902930302

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe distribution of vasopressin in the brain of the garden dormouse (Eliomys quercinus L.) was examined by immunocytochemistry at different times of the year. In spring‐summer, sexual dimorphism in the density of vasopressin labeling was observed in several areas of the brain. In these regions, such as the lateral septum and the nucleus of the vertical limb of the diagonal band of Broca, male garden dormice showed more vasopressin immunoreactivity than their female counterparts. In autumn‐winter, at the time of hibernation, vasopressin was undetectable in the sexually dimorphically innervated brain regions in males as well as females. In early spring, there was large variation in vasopressin staining in the male brain, whereas the female brain was consistently lacking in vasopressin labeling. In brain regions that exhibited no sexually dimorphic innervation in the summer, vasopressin labeling remained the same throughout the year. The difference in the amount of vasopressin immunoreactivity in males in summer and winter correlated significantly with differences in testes weight. In early spring, because of interindividual variations in the start of sexual activation, testes size does not correlate with the density of vasopressin immunoreactivity.Similar seasonal variations in density of vasopressin labeling in the brain were also observed in the European hamster(Cricetus cricetus). In this animal, central vasopressin infusion during the winter prevents hibernation. The presence of a similar pattern of changing vasopressin content in another hibernator, the garden dormouse, suggests an important role for this neuropeptide in seasonal functions.In the garden dormouse, vasopressin fibres could be detected in a number of brain regions where, in other rodents, such fibres are undetectable, e.g., the interpeduncular complex and the lateral superior olive. It is suggested that the central vasopressin system in the rat and European hamster is essentially the same as in the garden dormouse, but more difficult to detect immunocytochemica

ISSN:0092-7317    

DOI:10.1002/cne.902930303

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe diencephalic nucleus electrosensorius (nE) of gymnotiform fish comprises a series of finely tuned neuronal filters for control of the jamming avoidance response (JAR) and probably other electromotor tasks as well. The nE receives electrosensory input from the dorsal torus semicircularis (TSd) and octavolateral input from the ventral torus (TSv). The nE, in turn, projects to various hypothalamic and thalamic nuclei, including the prepacemaker nucleus (PPn), which can modulate the frequency of electric organ discharges (EODs) via its unique input to the medullary pacemaker nucleus.Four subdivisions of the nE can now be recognized: 1) The beat‐related area (nEb)‐‐‐a rostral cluster of tightly packed cells which receives TSd input and projects to the inferior lobe, anterior tuberal nucleus, anterior thalamic nucleus, central posterior thalamic nucleus, and PPn. The nEb contains neurons responsive to beat patterns caused by jamming stimuli. Stimulation of the nEb with L‐glutamate, however, fails to induce any EOD‐frequency shift. 2) The area causing EOD‐frequency rises (nE↑)‐‐a horizontal band of cells at the dorsal aspect of the caudal nE which receives TSd input and projects to the PPn and vicinity and to the cerebellum; nE↑ stimulation induces slow EOD‐frequency rises characteristic of the JAR. Responses of these cells to jamming stimuli are not yet known. 3) The area causing EOD‐frequency falls (nE↑)‐‐a horizontal band of cells at the ventral aspect of the caudal nE which receives TSd input and projects only to the PPn and vicinity; nE↑ stimulation induces slow EOD‐frequency falls characteristic of the JAR. The responses of these cells to jamming stimuli are not yet known. 4) The acousticolateral region (nEar)‐‐‐a complex medial region of the nE which receives input predominantly from the ventral torus and projects to the inferior lobe, anterior tuberal nucleus, central posterior thalamic nucleus, PPn, and cerebellum; the sensory and motor properties of this region are not known in detail, although auditory and mechanosensory responses have been recorded here. Projections to the PPn and its vicinity suggest direct control of electromotor behaviors by the nE, whereas thalamic and hypothalamic projections may provide a substrate for electrosensory influences on neuroendocrine and motivational control centers.The optic tectum projects strongly to the pretectum and various other diencephalic nuclei in the vicinity of the nE, but it does not innervate the nE itself. Accordingly, ablation of the tectum d

ISSN:0092-7317    

DOI:10.1002/cne.902930304

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe response of dorsal column axons was studied after neonatal spinal overhemisection injury (right hemicord and left doral funiculus). Rat pups (N = 11) received this spinal lesion at the C2 level within 30 hours after birth. The cauda equina was exposed 3 months later in one group of chronic operates (N = 5) and in a group of normal aduits (N = 2), and all spinal roots from L5 caudally were cut bilaterally; 4 days later the spinal cord and medulla were processed for Fink‐Heimer impregnation of degenerating axons and terminals. In a second group of chronic operates (N = 6) and normal adult controls (N = 4) the left sciatic nerve was injected with a cholera toxin‐HRP conjugate (C‐HRP), followed by a 2–3 day transganglionic transport period, and then the spinal cord and medulla were processed with tetramethylbenzidine histochemistry. Both control groups have a consistent dense projection in topographically adjacent regions of the dorsal funiculus and gracile nucleus. However, there is no sign of axonal growth around the lesion in either group of chronic experimental operates. Instead, there is a decreased density of projection within the dorsal funiculus near the lesion site. Many remaining C‐HRP labeled axons in the experimental operates have abnormal, thick varicosities and swollen axonal endings (5–10 μm × 10–30 μm) within the dorsal funiculus through several spinal segments caudal to the lesion. Ultrastructural analysis of the dorsal funiculus in three other chronic experimental operates reveals the presence of numerous vesicle filled axonal profiles and reactive endings which appear similar to the C‐HRP labeled structures.Transganglionic labeling after C‐HRP sciatic nerve injections (N = 4) and retrograde labeling of L4, L5 dorsal root ganglion neurons after fast blue injections of the gracile nucleus (N = 6) both suggest that all dorsal column axons project to the gracile nucleus in the newborn rat. Dorsal root ganglion (DRG) cell survival following the neonatal overhemisection injury was also examined in the L4 and L5 DRG. DRG neurons that project to the gracile nucleus were prelabeled by injecting fast blue into this nucleus at birth two days prior to the cervical overhemisection spinal injury. Both normal littermates (N = 9) and spinally injured animals (N = 12) were examined after postinjection survival periods of 10 or 22 days. Comparison of the percentage and number of labelled and unlabeled DRG neurons in the L4 and L5 ganglia in control and experimental operates reveals no sign of cell loss after neonatal dorsal colomn axotomy.We conclude that dorsal column axons do not grow around damage to their normal pathway in the newborn rat during a period when previous studies show adjacent corticospinal axons are able to grow around the same type of spinal injury and when the spinal environment normally permits growth of the still elongating corticospinal

ISSN:0092-7317    

DOI:10.1002/cne.902930305

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

年代:1990

数据来源: WILEY

摘要:

AbstractThis study focuses on the involvment of catecholamines and nine different peptides in efferents of the nucleus of the solitary tract to the central nucleus of the amygdala, the bed nucleus of the stria terminalis, and different parabrachial and hypothalamic nuclei in the rat. A double‐labeling technique was used that combines a protein‐gold complex as the retrograde tracer with immunohistochemistry.Catecholaminergic projection neurons were the most numerous type observed and projected mainly ipsilaterally to all targets studied. Most projections arose from areas overlying the dorsal motor nucleus, mainly the medial nucleus. Neurons synthesizing somatostatin, met‐enkephalin‐Arg‐Gly‐Leu, dynorphin B, neuropeptide Y, and neurotensin projected to all structures examined. Somatostatin and enkephalin immunoreactive projection cells were the most numerous. They were located in close proximity to each other, including all subnuclei immediately surrounding the solitary tract, bilaterally. Most dynorphin and neuropeptide Y immunoreactive projection cells were found rostral to that of enkephalinergic and somatostatinergic projections, and mainly in the ipsilateral medial nucleus. Neurotensinergic projections were sparse and from dorsal and dorsolateral nuclei.Substance P and cholecystokinin contribute to parabrachial afferents. The location of substance P immunoreactive projection cells closely resembled that of enkephalinergic and somatostatinergic projections. Projecting cholecystokinin immunoreactive cells were observed in dorsolateral nucleus. Bombesin immunoreactive cells in dorsal nucleus projected to either the parabrachial or hypothalamic nuclei. No vasoactive intestinal polypeptide‐containing cells were detected.Thus, most catecholaminergic and neuropeptidergic efferents originated from different populations of cells. It is proposed that catecholaminergic neurons constitute the bulk of solitary efferents and that they may contribute to autonomic neurotransmission. Peptidergic neurons mainly form other subgroups of projections and may play a role in modulating the physiological state of the

ISSN:0092-7317    

DOI:10.1002/cne.902930306

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe dendritic morphology of retinal ganglion cells was studied in flatmounted retinae of the marsupialSetonix brachyurus, quokka. In the adults, horseradish peroxidase (HRP) was applied to the vitread surface of flattened retinae. Wide‐, large‐, medium‐, and small‐field classes appeared to correspond to gamma, alpha, delta, and beta cells, respectively, in the cat (Boycott and Wässle,J. Physiol.249:397‐419, 1974).To reveal the early stages of dendritic development, HRP was placed on the optic nerve of isolated eye cups from the day of birth to postnatal day (P) 63 when the area centralis is beginning to form (Dunlop and Beazley,Dev. Brain Res.23:81‐90, 1985). Youngest cells lacked dendrites and had an elongate soma in the cytoblastic layer with an endfoot contacting the ventricular surface. Once in the ganglion cell layer, the soma was rounded and dendrites appeared as short, unbranched processes. Most cells were asymmetric or „polarised”︁ with the axon arising from the side nearest the optic disk and dendrites from the opposite side. Polarity was maintained in cells with longer, branched dendrites. A small proportion of cells exhibited a reversed polarity in which the axon arose from the side nearest the retinal edge and dendrites towards the disk. Cells appeared to acquire an approximately symmetric, adult‐like tree by the addition of new primary dendrites between the existing ones and the axon hillock. Wide‐, large‐, medium‐, and small‐field cells were evident from P6, P25, P31, and P40, respectively. Spines were observed on dendrites and axons during development but were rare in the adult. Some den‐dro‐axons were seen at all ages examined.The existence of an initial axodendritic polarity in retinal ganglion cells supports the hypothesis that the axon hillock is the determinant of dendritic geometry (Maffei and Perry,Dev. Brain Res.41:185‐194, 1988). Polarity may also contribute to the establishment of „radial orientation”︁ in which the long axis of the elliptical dendritic tree of cells outside the area centralis points towards central retina and the weighted centre is displace towards the retinal periphery (Leventhal and S

ISSN:0092-7317    

DOI:10.1002/cne.902930307

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe histology and location of human respiratory chemosensitive fields are not known. In contrast, the physiology of respiratory chemosensory areas in the ventral medulla of cats has been studied extensively, and their anatomy has been partially described. Using basic principles of comparative cytoarchitecture and computer‐aided reconstructions of serial‐sectioned medullae, we describe the histology and three‐dimensional distribution of putative respiratory chemosensors in the feline and human infant medulla. We found that ventrolateral neurons of the human nucleus conterminalis are homologous to neurons identified in the feline L chemosensitive field by Trouth and others, and that ventrolaterally situated neurons in the human arcuate nucleus correspond to neurons predominating in the feline S and M fields. In addition, there are foci of thickened marginal glia along the feline ventral medullary surface that colocalize with chemosensitive fields identified by physiologic studies reported by others; we identify similar foci in the infant medulla. Thickened marginal glia are intermixed with neuronal fibers, often adjacent to neurons of the feline chemosensitive fields and their human counterparts, suggesting that they constitute a chemosensory neuropil at the medullary surface. Computer‐aided reconstructions provide insight into the three‐dimensional topography of putative respiratory chemosensors and their relationships to other brainstem structures in ways not obvious in single or even multiple sections. This delineation of candidate human respiratory chemosensors is a first step toward their postmortem analysis in patients with central ventilatory control disorders where finding histological abnormalities in these sites would support their role in human ve

ISSN:0092-7317    

DOI:10.1002/cne.902930308

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

年代:1990

数据来源: WILEY

摘要:

AbstractThis study examines the termination pattern of axons from the medial mammillary nucleus within the ventral tegmental nucleus of Gudden (TV) in rats by using anterograde transport of horseradish peroxidase conjugated with wheat germ agglutinin (WGA‐HRP) and visualized with tetramethylbenzidine. The neuropil of TV contains three classes of axodendritic terminals, that is, terminals containing round, flat, and pleomorphic synaptic vesicles. These types make up 55.6%, 26.1%, and 18.3%, respectively, of all normal axodendritic terminals. Injection of WGA‐HRP into the medial mammillary nucleus permits ultrastructural recognition of anterogradely labeled terminals within the TV. More than 80% of the labeled terminals contain round synaptic vesicles and form asymmetric synaptic contacts, whereas about 16% contain flat synaptic vesicles with symmetric synaptic contacts. There are a few labeled terminals with pleomorphic vesicles and only a few axosomatic terminals. Almost all labeled terminals are small, having diameters of less than 1.5 μm. Compared with the distributions of normal and labeled terminals with round vesicles, there is an increase of the percentage of labeled terminals with round vesicles on the intermediate dendrites (1‐2 μm diameter) and a decrease on the distal dendrites (less than 1 μm diameter). Anterogradely labeled axon terminals often contact retrogradely labeled dendrites.These results suggest that the medial mammillary neurons send mainly excitatory as well as a few inhibitory inputs to the dendrites of TV and have direct reciprocal contacts with the TV

ISSN:0092-7317    

DOI:10.1002/cne.902930309

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

年代:1990

数据来源: WILEY

摘要:

AbstractGolden hamsters with established dominant/subordinate relationships communicate their social status by rubbing pheromone‐producing flank glands against objects in the environment. This behavior, called flank marking, is controlled by vasopressin‐sensitive neurons localized to the anterior hypothalamus. Vasopressinergic magnocellular neurons in the nucleus circularis and medial aspect of the supraoptic nucleus are thought to be a source of neurotransmitter for the initiation of flank marking.The present study was undertaken to examine the extrahypothalamic control of flank marking. The anatomical and functional connections between the lateral septum and the vasopressin‐containing nuclear groups in and around the anterior hypothalamus were examined by: (1) tracing afferent and efferent connections following microinjection of horseradish peroxidase and Phaseolus vulgaris‐leucoagglutinin into the lateral septum, and (2) recording odor‐induced flank marking prior to and following ibotenate lesions in the septum.The greatest number of perikarya retrogradely labeled with horseradish peroxidase were found lateral to the anterior hypothalamus and ventral to the fornix in the area of the lateral hypothalamus. The vasopressin‐containing nuclear groups, e. g., paraventricular, supraoptic, suprachiasmatic nuclei, and the nucleus circularis, were devoid of labeled perikarya. Nerve terminals anterogradely labeled with Phaseolus vulgaris‐leucoagglutinin were primarily localized to the anterior hypothalamus, in and around the nucleus circularis, and the medial aspect of the supraoptic nucleus. The lateral aspect of the supraoptic nucleus was devoid of nerve terminals as were the paraventricular and suprachiasmatic nuclei. The anatomical connections between the lateral septum and the hypothalamus appear to be necessary for the control of flank marking, since the microinjection of ibotenate into this limbic site significantly reduced odor‐induced flank marking as compared to control microinjectio

ISSN:0092-7317    

DOI:10.1002/cne.902930310

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe goal of this study was to elucidate the precise regional and laminar distribution of neuropeptide Y (NPY) binding sites in feline and primate visual cortex. By means of in vitro receptor autoradiography, NPY binding sites in primate and feline visual cortex were specifically labeled with3HNPY. In cat area 17, the highest density of NPY‐binding sites was present in lamina I and the upper half of lamina II. The density then gradually decreased towards lamina VI. Areas 18 and 19 exhibited a similar binding site‐density profile. The decrease in density from superficial to deep layers was more gradual in area 18 than in areas 17 and 19. In monkey primary visual cortex (V1), layer IVc presented a high concentration of NPY binding sites, in addition to a dense zone of binding sites in layer I. Monkey secondary visual cortex (V2) displays a similar dense zone in layer I, but lacks such high density of NPY binding sites in layer IV. Therefore, the border between primary and secondary visual cortex coincides with the abrupt disappearance of this latter high density in layer IV. In cat as well as in monkey visual cortex, no significant differences were found between regions representing central vision and those representing the peripheral parts of the visual field. Comparison of our results for NPY binding sites with the distribution of alpha1‐adrenergic receptors, as recently described by Rakic et al. (J. Neurosci. 8(10):3670‐3690, 1988) for primate and Parkinson et al. (Brain Res. 457:70‐78, 1988) for feline visual cortex, revealed that those two patterns are ver

ISSN:0092-7317    

DOI:10.1002/cne.902930311

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

年代:1990

数据来源: WILEY