摘要:

AbstractRabbit retinae were stained with antibodies to glial fibrillary acidic protein (GFAP) at various times up to 5 months after complete unilateral intraorbital optic nerve transection, which is known to induce degeneration of ganglion cell axons and perikarya in the retina. A transient immunoreactivity for GFAP was observed in Müller glial cells that normally lack this marker. Müller‐cell GFAP immunoreactivity became detectable 4 days after the lesion, but Müller cells were no longer labeled 3 months later. GFAP‐labeled astrocytes located in the nerve fiber layer showed no change in immunoreactivity at any stage after transection.Application of horseradish peroxidase to the left and right superior colliculus of a rabbit whose optic nerve had been transected unilaterally 2 years before confirmed the completeness of the transection. Yet electron microscopy showed the presence of some healthy‐looking ganglion cell axons in the lesioned retina, although these cells were deprived of their target.Labeling retinal wholemounts with neurofilament antibodies confirmed the presence of some ganglion cell axons and perikarya in the retina more than 2 years after transection. The course of these axons suggested that they were remnants of axons. Using antibodies to galactocerebroside (GC) we found that, as in the normal rabbit, these persisting ganglion cell axons were myelinated in the medullary rays. Although many ganglion cell axons had disappeared after 2 years, the number of neuroglial cells (including astrocytes and oligodendrocytes) present in the medullary ray region was not altered. The cell bodies of some oligodendrocytes were covered with a myelin sheath, an aberrant feature not seen

ISSN:0092-7317    

DOI:10.1002/cne.903120202

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

年代:1991

数据来源: WILEY

摘要:

AbstractThis work describes the retinal origin of the crossed and uncrossed projections in newborn, 9‐day‐old and adult normally pigmented and albino ferrets. Horseradish peroxidase (HRP) was injected unilaterally into the thalamic and midbrain visual centers of ferrets to label retinal ganglion cells retrogradely.In normally pigmented adults, the retinal line of decussation was sharp and passed through the area centralis. Ganglion cells with uncrossed axons occupied the entire temporal retina. In albino adults, ganglion cells with uncrossed axons were distributed in the periphery of the temporal retina away from the area centralis. In the normally pigmented adults, about 11% of the retinal ganglion cells had uncrossed axons compared to about 4% in the albinos. At birth, normally pigmented ferrets had a sharp line of decussation with most (about 98%) uncrossed ganglion cells found in the temporal retina. In the newborn albinos, most uncrossed ganglion cells were in the temporal retina (about 89%), but there were many fewer than in the normal neonates and, as in the albino adults, the uncrossed ganglion cells were distributed along the temporalmost margin of the retina. In the normal neonates, about 11% of the ganglion cells had uncrossed axons, compared to about 3% in the albino neonates. The area centralis and visual streak were not evident until 9 days after birth.From these results we conclude that the retinal line of decussation is essentially mature by birth in the ferret, and the degree of t he albino's abnormality is as extreme in neonates as in adults. The retinal decussation is virtually mature at a stage of development when the crossed and uncrossed retinal afferent axons are completely intermingled in their target nuclei and prior to the onset of significant retinal ganglion cell l

ISSN:0092-7317    

DOI:10.1002/cne.903120203

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe intrinsic muscles and peripheral nerves in the buccal system of the sea hareAplysia californicawere studied to build a foundation on which to base future investigations of feeding in intact animals. A detailed description of the bilaterally paired intrinsic muscles is given identifying previously unreported muscles. Each of the six buccal nerves (n1‐n6) and the cerebrobuccal connective (CBC) have been characterized in several respects. Cell bodies in the buccal ganglion with projections into each of the buccal nerves have been identified via the cobalt backfilling technique. All nerves contain axons of cell bodies in the ipsilateral as well as the contralateral ganglia. For each nerve, there is a consistent pattern in the distribution of cell bodies in the paired ganglia with the number of cell bodies in the contralateral ganglion being less than or equal to the number in the ipsilateral ganglion. Although the total number of backfilled cell bodies varies among the nerves, their size ranges are similar with the majority being small. Nerves 1, 2, 4, 5, and 6 provide motor innervation to the intrinsic buccal muscles in varying degrees with nerve 4 supplying all the intrinsic muscles; nerve 2 supplies only one. The axon composition of each nerve was scrutinized and revealed large numbers of axon profiles, the majority of which were less than 2 μm in diameter. The present study provides a framework for analysis of feeding behavior inAplysia californi

ISSN:0092-7317    

DOI:10.1002/cne.903120204

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe visual cortical serotoninergic system was compared in normal and dark‐reared cats to determine whether visual experience is necessary for its normal development. In vitro receptor binding of [3H]5‐HT indicated an increase in 5‐HT1receptor number in dark‐reared cats with no change in affinity. This elevation was specific to the visual cortex and no changes were found in the frontal cortex as a result of dark rearing. Autoradiographic histology revealed that in the normal cat visual cortex, 5‐HT1receptors were present in all cortical layers and were slightly more dense in supragranular and infragranular layers. In dark‐reared cats, there was a marked elevation in receptor density in supragranular and infragranular layers and little change within layer IV.Immunohistochemical techniques (anti‐5‐HT) were used to compare serotoninergic innervation in the visual cortex of normal and dark‐reared cats. In normal cat visual cortex, serotonin fibers were most dense in the superficial layers (I‐III), least dense in layers IV and VI, and intermediate in layer V. No differences were found between normal and dark‐reared cats in the laminar distribution or density of serotoninergic innervation.These results indicate that visual experience is necessary for the normal development of the visual cortical serotonin system. The findings that the effects of dark rearing were specific to the visual cortex and that within the visual cortex these effects were specific to supra‐ and infragranular layers are consistent with a possible role for serotonin in the prolonged physiological plasticity that occurs in the visual cor

ISSN:0092-7317    

DOI:10.1002/cne.903120205

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

年代:1991

数据来源: WILEY

摘要:

AbstractIn this study the medial terminal nucleus (MTN) projection to the nucleus of the optic tract (NOT) was investigated in pigmented rats at the light and electron microscopical levels with a new combination of techniques. MTN terminals were anterogradely labeled with Phaseolus vulgaris‐leucoagglutinin (PHA‐L). Preembedding immunocytochemistry, followed by gold intensification, was used to visualize PHA‐L. Postembedding immunocytochemistry with 15 nm immunogold particles was carried out to demonstrate the inhibitory neurotransmitter gamma‐aminobutyric acid (GABA). Both PHA‐L and GABA labeling can be easily discriminated at the electron microsopical level even when present in the same neuronal profiles.Light microscopically MTN‐NOT fibers proved to have several branches with many varicosities. MTN terminals were found concentrated in terminal fields. Electron microscopically, it was shown that MTN boutons display characteristics resembling F‐type terminals, i.e., terminals with dark mitochondria, pleomorphic vesicles, and symmetrical synapses. All NOT afferents originating from the MTN contained GABA and made multiple contacts exclusively with GABA negative NOT somata and dendrites. These results indicate the existence of a strong and direct inhibitory input onto GABA negative projection neurons in the NOT. This substantiates earlier physiological and morphological reports. It was further demonstrated that the location and organization of MTN terminals in the neuropil differ from that of the retinal input: MTN terminals are largely separated from retinal terminals. MTN terminal fields contain large amounts of GABA positive F terminals in contrast to retinal terminal areas. MTN terminals take part in irregularly shaped agglomerations of terminals, which contain many F terminals and dendritic processes and are surrounded by a glial sheet. Retinal terminals are found grouped together in small circular arrangements contacting a cen

ISSN:0092-7317    

DOI:10.1002/cne.903120206

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

年代:1991

数据来源: WILEY

摘要:

AbstractA naturally occurring species‐specific membrane marker was used to identify unambiguously transplanted septal cells and their fibers which have grown into host tissue. Cell suspensions of the septum/basal forebrain region of C57B1/6 mouse embryos were transplanted into the dentate gyrus of Sprague‐Dawley rats that had received a fornix lesion. The membranes of the mouse contained Thy‐1.2, while the membranes of the rat contained Thy‐1.1. An antibody to Thy‐1.2 clearly identified the donor tissue and did not react with the Thy‐1.1 of the host's membranes. The ultrastructure of the immunoreactively labeled tissue confirmed previous biochemical findings on the distribution of Thy‐1 and showed Thy‐1.2 immunoreactivity on axons and dendrites, microtubules, some mitochondrial membranes, and the surface membranes of cell bodies. Within the transplant, a few glial profiles showed immunoreactive fibrils, but most glial profiles within the transplant and all glial profiles outside the transplant were not immunoreactive. Astrocyte fibers enclosed the outgrowing labeled fibers to form fascicles, but did not penetrate the fascicle. There was no other distinctive association of astrocytic profiles with immunoreactive fibers. Dendrites grew for long distances into the host's molecular layer. Many immunoreactive dendritic profiles formed synapses with unlabeled terminal profiles from the host. The host synapses on the long dendrites of the transplanted neurons may form an important source of input for the initiation of physiological activity in the new circuits established by the transplant. A few labeled (donor) synaptic terminals were observed in the molecular layer, but Thy‐1.2‐labeled dendritic profiles were much more prominent than labe

ISSN:0092-7317    

DOI:10.1002/cne.903120207

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

年代:1991

数据来源: WILEY

摘要:

AbstractVasoactive intestinal peptide (VIP) is a 28‐amino acid peptide that has been demonstrated to reside in cells (=VIP+ cells) of the retinae of various vertebrate species. In an attempt to study the morphology and distribution of VIP+ cells in the retina of the rhesus monkey in more detail, we subjected VIP+ cells observed in cryostat sections or wholemounts of rhesus monkey retinae to a quantitative analysis. VIP+ cells were found to reside in the innermost row of the inner nuclear layer (INL) and in the ganglion cell layer (GCL) in similar numbers (estimate: 50 cells/mm2at 6–10 mm eccentricity each) and only on rare occasions (12% of all VIP+ cells) in varying positions within the inner plexiform layer (IPL). Somata of VIP+ cells were circular and had a mean diameter of 9.1 μm. They gave rise to 1–3 main dendrites, which were usually oriented toward the IPL. Main dendrites ramified widely into thin fibers (dendritic field diameter<= 1 mm), carrying varicose swellings. The fibers that contributed to one and the same plexus of VIP+ fibers preferred the middle third of the IPL, independent of the positions of the parent somata. A quantitative analysis of nearest‐neighbour distances in the retinal wholemount preparation suggested that VIP+ cells in the GCL and in the INL might be distributed according to 2 independent mosaics. A comparison with Golgi‐stained material leads to the tentative equation of VIP+ cells with the “spiny” A12 amacrine cell of Mariani ('90). Whereas the low density and large dendritic field size of VIP+ cells might suggest a more widespread function, the varicose dendritic morphology seems to be more compatible with functionally independent dendritic subunits mediating loc

ISSN:0092-7317    

DOI:10.1002/cne.903120208

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

年代:1991

数据来源: WILEY

摘要:

AbstractEach antennal lobe in the brain of a male moth has a distinctive neuropil structure, the macroglomerular complex (MGC), which is specialized for primary processing of information about the conspecific female sex‐pheromone blend. Olfactory interneurons with dendritic arborizations in the MGC were examined by means of tandem intracellular recording and staining with Lucifer Yellow. Neurons that responded selectively to stimulation of the antenna with the major pheromone component, (E,Z)‐10,12‐hexadecadienal, had arborizations that were restricted to a toroidal subdivision (the “toroid”) of the MGC. Similarly, neurons that responded selectively to antennal stimulation with (E,Z)‐11,13‐pentadecadienal, a more stable mimic of a second essential but chemically unstable pheromone component, (E,E,Z)‐10, 12, 14‐hexadecatrienal, had arborizations confined to a globular subdivision (the “cumulus”) of the MGC situated more proximally to the antennal nerve input. One neuron that responded to both of these stimuli clearly had arborizations in both subdivisions of the MGC. These anatomically distinct subdivisions of the MGC thus appear also to be functionally separate regions of pheromon

ISSN:0092-7317    

DOI:10.1002/cne.903120209

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

年代:1991

数据来源: WILEY

摘要:

AbstractRelatively little is known about the spatial organization of spinal nociceptive processing. This study has employed the expression ofc‐fos‐like protein as a marker for neuronal activity and has analyzed the patterns of immunoreactivity seen within the rodent spinal cord following noxious mechanical stimulation of various portions of one hindlimb.The results indicate that noxious mechanical stimulation induces distinct, somatotopic patterns of immunolabeling in laminae I‐IV. Individual digits of a foot are represented medially in the dorsal horn over a short rostrocaudal distance, with the most lateral digit represented approximately one segment caudal to the most medial digit. Representation of the hip region is more lateral, is centered at L2, and extends rostrocaudally over many segments.The patterns of neuronal excitation seen in laminae V‐IX following noxious peripheral stimulation were similar to those noted in laminae I‐IV but were less tightly organized.C‐fos‐like immunoreactivity was noted both medially and laterally in the deeper laminae following stimulation of any portion of the hindlimb, but stimulation of different areas produced different columns of labeled cells extending from the superficial dorsal horn into lamina VII. In the rostrocaudal direction, immunolabeling in lamina V‐IX was maximal at the same segmental level as in laminae I‐IV, but the more ventral laminae exhibited increases inc‐fos‐like immunoreactivity over longer rostrocaudal distances.Experiments in spinally transected animals indicated that long, descending pathways contributed little or nothing to the pattern of immunolabeling.The results of this study imply that spinal nociceptive processing is spatially organized not only in laminae I‐IV, but also in more ventral reg

ISSN:0092-7317    

DOI:10.1002/cne.903120210

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

年代:1991

数据来源: WILEY

摘要:

AbstractAngiotensin II (Ang II) binding sites were localized in the thalamus, basal ganglia, midbrain, and pons of the human central nervous system by in vitro autoradiography, employing125I‐[Sar1Ile8]angiotensin II as the radioligand. High‐density binding occurs in the substantia nigra pars compacta, the interpeduncular nucleus and two of the raphe nuclei, the raphe magnus, and median raphe nucleus. Moderate densities occur in the caudate nucleus, putamen, bed nucleus of the stria terminalis, rostral linear nucleus, caudal linear nucleus, dorsal and paramedian raphe nuclei, locus coeruleus, and region of the subcoeruleus, oral dorsal paramedian nucleus, and A5/periolivary region. Low levels occur in the region between the subthalamic nucleus and the zona incerta, the mediodorsal thalamic nucleus, the central gray, the lateral and medial parabrachial nuclei, and the molecular layer of the cerebellum.The high density of Ang II receptor binding in the substantia nigra occurs over pigmented, presumably dopaminergic, neurons. The binding in this site, and in the striatum, is not observed in any of the other species we have studied. It displays similar pharmacological characteristics to the Ang II receptor binding site in other regions of the human brain.Overall we demonstrate a discrete pattern of Ang II receptor binding sites in the human brain, which shows a high correlation with the distribution observed in other mammalian spec

ISSN:0092-7317    

DOI:10.1002/cne.903120211

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

年代:1991

数据来源: WILEY