摘要:

AbstractA monoclonal antibody to choline acetyltransferase (ChAT) was utilized for immunocytochemical identification of cholinergic neurons in the basolateral hypothalamus. Light and electron microscopic examination revealed a network of cell bodies, dendrites, and axonal processes dorsolateral to the supraoptic nucleus. Within this region the cells immunoreactive for ChAT receive numerous unlabeled terminals which contact dendrites, cell soma, axons and occasional somatic spines. In a few cases, small ChAT‐immunoreactive terminals were observed contacting a cholinergic cell soma or large dendrite. Many ChAT‐immunoreactive fibers were directed toward the supraoptic nucleus forming a dense local network but very few of these fibers penetrated deeper than approximately 20 μm into the supraoptic nucleus. A total of 63 ChAT‐immunoreactive terminals were mapped within the basal hypothalamus, of which the vast majority contacted unlabeled dendrites immediately dorsolateral to the supraoptic nucleus. Labeled terminals were rare or nonexistent in the medial portions of the hypothalamus or deep within the supraoptic nucleus. This pattern of ChAT terminal densities correlates with the distribution of binding for the muscarinic cholinergic probe, [3H]quinuclidinylbenzilate, but not the binding of the putative nicotinic cholinergic probe, [125I]alpha‐bungarotoxin, which is high within the supraoptic nucleus. Thus, the cholinergic neurons of the basal hypothalamus appear to form a network of intrinsic connections which probably represent input to muscarinic cholinergic receptors. No evidence was found to suggest that cholinergic presynaptic terminals were colocalized with the alpha‐bungarotoxin binding protein within the supraopt

ISSN:0092-7317    

DOI:10.1002/cne.902760202

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

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper reports the pattern of labeling in the cat superior colliculus produced by an antiserum raised against BSA‐conjugated gamma aminobutyric acid (GABA) and visualized by light and electron microscope immunocytochemistry. Neuropil labeling was densest within the zonal and superficial gray layers but was also found in the deep layers. Neurons labeled by the GABA antibody were also most dense within the zonal and superficial gray layers, although many labeled neurons were also found in the deeper layers. The ratio of labeled to unlabeled cells varied from an average of 45% in the superficial subdivision and the intermediate gray layer to less than 30% in the deeper laminae. Almost all intensely labeled cells were small (mean area = 127 μm2) and had varied morphologies.Several types of labeled cell were observed with the electron microscope. One type had a horizontal, fusiform cell body and a deeply invaginated nucleus. Another type had a small round or ovoid cell body with cytoplasm clumped at one end. Labeled cells with other morphologies were also occasionally seen. No labeled glial cells were found. Two types of vesicle‐containing dendrite were stained by the GABA antibody. One type had loose accumulations of small synaptic vesicles and often received input from retinal terminals. Another type had spines also containing small synaptic vesicles. Labeled dendrites without synaptic vesicles were also seen frequently. Putative axon terminals labeled by the GABA antibody had densely packed synaptic vesicles and formed symmetric synaptic contacts. Labeled myelinated axons were also commonly found.These results confirm those using uptake of tritiated GABA (Mize et al.:J. Comp. Neurol. 202:385‐396, '81,J. Comp. Neurol, 206:180‐192, '82) in that two of the same classes of GABA neuron, horizontal I and granule I cells, were identified in the superficial laminae. However, the GABA antiserum used in this study also revealed a third class of GABA neuron with vesicle‐containing spines. The antiserum also labeled a significant number of putative GABAergic neurons located in the deep subdivision of the cat superior colliculus which were not previously recognized by using transmitter autor

ISSN:0092-7317    

DOI:10.1002/cne.902760203

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

年代:1988

数据来源: WILEY

摘要:

AbstractThis study examines the dorsal nucleus of the lateral lemniscus (DNLL) and its afferent and efferent connections. In Nissl‐stained material, DNLL has three parts: dorsal, ventral, and lateral. Although each part contains neurons with similar Nissl patterns, the subdivisions may be distinguished by the size, shape, and orientation of the cells. The lateral DNLL contains a mixture of DNLL neurons and cells from the sagulum.Afferent connections to DNLL were investigated with anterograde axonal transport techniques. Bilateral inputs to DNLL arise from the anteroventral cochlear nucleus and lateral superior olive, while unilateral inputs are provided by the ipsilateral medial superior olive and the contralateral DNLL. The inputs appear to have a tonotopic organization. Afferent fibers to DNLL form horizontal bands that are continuous both mediolaterally and rostrocaudally. All parts of DNLL do not share the same inputs, and a medial‐to‐lateral gradient in the labeling of some pathways is evident.To study the efferent connections of DNLL, both retrograde and anterograde axonal transport techniques were used. The DNLL projects to the inferior colliculus and the contralateral DNLL. The topography of these projections suggests that areas of similar tonotopic organization are connected. In the inferior colliculus, the projection is heaviest to the central nucleus and extends to the adjacent dorsal and caudal cortex, the rostral pole nucleus, and the ventrolateral nucleus. Axons from DNLL terminate along the fibrodendritic laminae of the central nucleus as bands that are prominent on the contralateral side, whereas those on the ipsilateral colliculus are more diffuse.The afferent and efferent connections of DNLL constitute a multisynaptic pathway, parallel to the other ascending pathways to the inferior colliculus. The other ascending pathways include the direct pathways from the cochlear nucleus to the inferior colliculus and the indirect pathways via the superior olivary complex. Ascending pathways are discussed as to their relationship to the subdivisions of the inferior colliculus, the laterality of their projections, and their banding patterns in the central nucleus. In contrast to the excitatory pathways to the inferior colliculus, the neurons in DNLL may use GABA as a neurotransmitter. Axons from the DNLL terminate in the inferior colliculus as bands that could have a unique inhibitory function. Thus, the multisynaptic, DNLL pathway may provide feed‐forward inhibitory inputs to the inferior colliculus, bilaterally, and to the contralater

ISSN:0092-7317    

DOI:10.1002/cne.902760204

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe “transmitter‐specific” retrograde axonal tracer3H‐D‐asparate has been used to demonstrate neurons in the olfactory bulb which putatively utilize aspartate and/or glutamate as their neurotransmitter and which send an axon either to the piriform cortex or within the bulb itself.Injections of3H‐D‐aspartate into layer I of the anterior piriform cortex, in the zone of termination of axons from the olfactory bulb, labeled only a few cells in the main olfactory bulb, located in the mitral and external plexiform layers. Although these cells resembled mitral and external plexiform layers. Although these cells resembled mitral and tufted cells, they tended to have smaller somata than other mitral or tufted cells and apparently form a distinct subpopulation of relay cells. In contrast, many of the mitral cells of the accessory olfactory bulb were labeled by the same injections of3H‐D‐aspartate, probably as a result of involvement of the accessory olfactory tract or its bed nucleus in the injection site. Similar injections of the “nonspecific” tracer HRP into the anterior piriform cortex labeled most of the cells in the mitral cell layer of both the main and accessory olfactory bulbs, and some tufted cells in the external plexiform layer. It is concluded that only a small, distinct subpopulation of the mitral or tufted cells of the main olfactory bulb are aspartatergic and/or glutamatergic, while many (at least) of the mitral cells of the accessory olfactory bulb use the excitatory amino acids as transmitters.Injections of3H‐D‐aspartate directly into the main olfactory bulb also failed to label the mitral and deeply situated tufted cells. However, a few cells were labeled in the periglomerular region, the superficial external plexiform layer, and the granule cell layer near the injection site. These labeled cells were smaller than mitral and tufted cells but generally larger than periglomerular or granule cells. They may represent a population of glutamatergic or aspartatergic short axon cells. In addition, small cells of an unknown type were labeled in the olfactory nerve layer following injections in the deepest part of the bulb. These cells do not correspond to any of the well characterized cell ty

ISSN:0092-7317    

DOI:10.1002/cne.902760205

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

年代:1988

数据来源: WILEY

摘要:

AbstractCholecystokinin (CCK) binding sites were localized in the hippocampus, amygdala, and medial temporal cortices of macaque monkeys by using techniques of in vitro receptor autoradiography. Binding sites were labeled with3H‐CCK‐8 and125I‐CCK‐33, and nonspecific binding was assessed in the presence of 1 μM CCK‐8. Comparison of autoradiograms with Nisslstained sections allowed precise correlation of autoradiographic grain distribution with cytoarchitecture.CCK binding in the amygdala varied among nuclear subdivisions. It was dense in the lateral, basomedial, endopiriform, and cortical nuclei, in the parvicellular portion of the accessory basal nucleus, the periamygdaloid cortex, the cortical transition area, and in the amygdalohippocampal area. Labeling was sparse in the central, medial, and basolateral nuclei as well as in the magnocellular accessory basal nucleus. In the hippocampal formation, a single dense band of CCK binding was observed over the granule cell layer and adjacent few millimeters of the molecular layer of the dentate gyrus, while in the polymorph and remaining portions of this layer binding was of very low density. Prominent label over the pyramidal layer in the presubiculum clearly distinguished this region from the adjacent subiculum in which binding just exceeded background levels. Moderate to light label was observed in the hilus and stratum pyramidale of CA3, CA2, and CA1, while other hippocampal layers showed minimal specific binding.Variation in CCK binding in the medial temporal cortex showed close correspondence to cytoarchitectonic subdivisions. In entorhinal cortex, for example, binding was concentrated in layers III‐VI while label in area 35 was prominent in all laminae except layer IV. Area TH of von Bonin and Bailey ('47) was distinguished from other regions by evenly distributed binding across all layers, while in area TF a bilaminar pattern of label in layers II and IV was observed.The highly specific patterns of CCK binding in amygdala and transitional cortices of the medial temporal lobe can be related to terminal fields of neo‐ and allocortical afferents to these regions, while label in the hippocampal formation coincides with the terminals of intrinsic neurons which ramify among the somata of cells that are targets of neocortical afferents. Thus, in all structures of the medial temporal lobe the disposition of peptidergic binding sites suggests that CCKergic systems may be important in the modulation of cort

ISSN:0092-7317    

DOI:10.1002/cne.902760206

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe mechanisms that control cell proliferation in the developing nervous system are not well understood. In larval and adult goldfish addition of new retinal neurons continues as the eye grows, but the factors that modulate the rate of cell proliferation are unknown. The eyes of Black Moors grow excessively during postembryonic life, probably as a direct result of abnormally elevated intraocular pressure. Ocular growth must be partly autonomous in Black Moors because in some individuals the two eyes are very different in size. To determine whether cell proliferation and neuronal cell number in the retina were correlated with size of the eye, we counted dividing neuronal progenitor cells (rod precursors) and mature retinal neurons (ganglion cells) in the retinas of ocularly asymmetric fish. Rod Precursors, which are scattered across the retina in the outer nuclear layer, were labeled with3H‐thymidine and counted on histological sections processed for autoradiography. Ganglion cells were counted in retinal whole mounts. We found that the total population of dividing rod precursors and the total number of ganglion cells were systematically greater in the large eye compared to the small eye of individual fish. We conclude that control of the rate of neuronal proliferation in the teleost retina is intrinsic to the eye and is probably regulated by the same factors that control ocular growt

ISSN:0092-7317    

DOI:10.1002/cne.902760207

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

年代:1988

数据来源: WILEY

摘要:

AbstractImmunohistochemical methods were utilized to systematically map the distribution of corticotropin‐releasing‐factor‐like immunoreactivity (CRF‐LI) in the diencephalon, mesencephalon, and rhombencephalon of two monkey species (Saimiri sciureusandMacaca fascicularis). A primary antiserum directed against the human form of the peptide was utilized. Immunoreactive neuronal perikarya and processes were evident in numerous areas, and the distributions of these elements were similar for the two species. As previously reported for rats, monkeys, and human, intense immunoreactivity was evident in putative hypophyseal neurons in the parvicellular component of the paraventricular nucleus of the hypothalamus and in fibers extending from this area into the median eminence. The results for other brainstem regions, most of which have been previously examined for CRF‐LI only in rats, indicate that many similarities exist between rats and monkeys in the distribution of this peptide in brainstem extrahypophyseal neuronal circuits, although substantial differences are also evident. For example, immunoreactive perikarya previously observed in other hypothalamic nuclei in rats were not evident in monkeys. Conversely, in monkeys, unlike rats, labeled perikarya were evident in several thalamic nuclei, especially in the intralaminar complex. Also, two large groups of immunoreactive neurons which have generally not been observed in rat studies were present in the mesencephalon and rhombencephalon. In the mesencephalon this consisted of a group of neurons just lateral to the mesencephalic tegmentum, extending throughout the rostral‐caudal extent of the midbrain. In the rhombencephalon, labeled perikarya were observed throughout the inferior olive. Some of the differences between rats and monkeys in the locations of labeled perikarya may be due to differences in antiserum specificity and/or sensitivity, or they may result from the fact that colchicine pretreatment was not utilized in the present study.The distributions of immunoreactive fibers also exhibited similarities and differences between monkeys and rats. The most striking terminal fields observed in the present study which have not been previously described are a moderate‐to‐dense field within and adjacent to presumed dopamine‐containing neurons in the substantia nigra pars compacta, a dense innervation of certain subdivisions of the interpeduncular nucleus, and a regionally and parasagittally organized distribution of fibers in the Purkinje cell and molecular layers of the cerebellar cortex.Thus, the present results suggest that there are substantial differences between rodents and primates in the cellular distribution of CRF‐LI in the brain and spinal cord. However, technical differences between the rat and monkey experiments may account for some of these contra

ISSN:0092-7317    

DOI:10.1002/cne.902760208

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

年代:1988

数据来源: WILEY

摘要:

AbstractIntracellular labeling of neurons permitted a direct correlation of neuronal profiles with sensory modality of cutaneous receptors. In the guinea pig, 47 neurons in the dorsal root ganglion (displaying C‐fiber conduction velocities) were labeled with horseradish peroxidase (HRP) by iontophoresis after determining the sensory modality. Receptive fields were explored with systematic “natural” stimuli. Cell areas of all C‐fiber units were measured by tracing the cellular contour in light microscopy. The mean cellular diamter calculated from cell areas was 21.8 μm in the second cervical ganglion of the guinea pig. Mean cell diameter for high‐threshold mechanoreceptors was 20.9 μm, 24.6 μm for polymodal nociceptors, and 25.7 μm for mechanicalcold nociceptors. Electron microscopic observations showed that all labeled neurons of C‐fiber units had profiles of small, dark type‐B neurons. Neurons representative of each sensory modality exhibited different cell features, each belonging to a distinct subtype of small B neurons. High‐threshold mechanoreceptor and mechanical‐cold nociceptor displayed a peripheral lamellar arrangement of cisternae of endoplasmic reticulum (ER), corresponding to the B1 subtype. Polymodal nociceptor units were characteristically of the B2 subtype, in which stacks of long and short cisternae of ER were distributed randomly throughout the cytoplasm, and the arrangement of Golgi bodies varied among these cells. Cooling receptors displayed poorly developed, flattened cisternae of ER and numerous vesicles, typical of the B3 subtype. These results imply that all C‐fiber cells belong to the small B‐type cell category and that the ultrastructural features of the neuron in the dorsal root ganglion may reflect the sensory modali

ISSN:0092-7317    

DOI:10.1002/cne.902760209

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

年代:1988

数据来源: WILEY

摘要:

AbstractWe studied the spinal projections of the medial and posterior articular nerves (MAN and PAN) of the knee joint in the cat with the aid of the transganglionic transport of horseradish peroxidase. The afferent fibers of the MAN entered the spinal cord via the lumbar dorsal roots L5 and L6 and those of the PAN entered via the dorsal roots L6 and L7. Within the dorsal root ganglia, most labeled neurons had small to medium diameters. A relatively higher number of medium‐size cell bodies were labeled from the PAN than from the MAN. In the spinal cord labeled MAN afferent fibers and terminations were most dense in the L5 and L6 segments, and those of the PAN were most dense in L6 and L7, that is, in the respective segments of entry. Labeled afferent fibers from both nerves projected rostrally at least as far as L1 and caudally as far as S2. Labeled fibers were found in Lissauer's tract as well as in the dorsal column immediately adjacent to the dorsal horn. In the spinal gray matter, both nerves had two main projection fields, one in the cap of the dorsal horn in lamina I, the other in the deep dorsal horn in laminae V‐VI and the dorsal part of lamina VII. Both nerves, but particularly the PAN, projected to the medial portion of Clarke's column. No projection was found to laminae II, III, and IV of the dorsal horn or to the ventral horn. Since these findings parallel observations on hindlimb muscle afferent fibers, the present data support the existence of a common pattern for the central distribution of deep somatic afferent fib

ISSN:0092-7317    

DOI:10.1002/cne.902760210

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

年代:1988

数据来源: WILEY

摘要:

AbstractThis study was undertaken to reveal the cellular stores of histamine in developing rat brain and to determine the stage of development during which the histamine‐immunoreactive neurons can first be detected. Rats from embryonal day 12 to postnatal day 14 were studied. The brains were fixed in 4% 1‐ethyl‐3(3‐dimethylaminopropyl)carbodiimide and standard immunofluorescence technique was used.The first histamine‐immunoreactive neurons were seen on embryonic day 13 in the border of mesencephalon and metencephalon. On embryonic day 15 immunoreactive neurons were detected in ventral mesencephalon and rhombencephalon. In caudal, tuberal, and postmammillary caudal magnocellular nuclei histamine‐immunoreactive neurons were first detected on embryonic day 20 while those in the hindbrain had disappeared. Histamine‐immunoreactive nerve fibers were first detected on embryonic day 15 in rhombencephalon and mesencephalon and in some areas of diencephalon including the mammillary bodies and frontal cortex. On embryonic day 18 the number of immunoreactive nerve fibers in the hindbrain had decreased considerably, but the olfactory bulb, septal and hypothalamic area, and the cerebral cortex showed immunoreaction in fibers. The density of histamine‐immunoreactive fiber networks increased until postnatal day 14 when an adultlike pattern of neurons and fibers had developed.Histamine‐immunoreactive neurons are present in embryonal CNS and they develop extensive projections to va

ISSN:0092-7317    

DOI:10.1002/cne.902760211

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

年代:1988

数据来源: WILEY