摘要:

AbstractOFF‐center amacrine cells were intracellularly recorded and stained with Lucifer yellow to investigate the cell correlations between photoresponses and morphological features.All OFF‐amacrine cells were monostratified and branched within the outer half of the inner plexiform layer. In the flat‐mounted retina, however, three distinct morphological classes were distinguishable, which correlated with observed physiological differences.Class 1 consisted of wide‐field, stellate amacrine cells with long, thin processes, which branched only close to the soma. The diameter of the circular dendritic field ranged from 0.8 mm to 2.0 mm. Their photoresponse to spot stimulation was a hyperpolarization during light‐ON and a small depolarization after light‐OFF. They showed strong antagonistic center‐surround organization of the receptive field. Its size was approximately equal to the dendritic field size.Class 2 consisted of wide‐field, giant amacrine cells with a „central”︁ dendritic field formed by thick dendrites, and a „peripheral”︁ dendritic field formed by a few long and thin, „axonlike”︁ processes. The shape of the dendritic field was elongated, with the long axis parallel to the visual streak. Their receptive field size was considerably smaller than their dendritic field size, which was several millimeters of diameter along the long axis. Their photoresponse to spot stimulation was a fast depolarization after light‐OFF, and about 50% of these cells showed strong antagonistic center‐surround receptive field organization.Class 3 consisted of small‐ or medium‐field, „starburstlike”︁ amacrine cells with circular dendritic fields of 0.1 mm to 0.6 mm diameter. Their fine, beaded dendrites branched predominantly in the distal parts of the dendritic field. Their photoresponses to light were similar to the of the giant amacrine cells; however, their receptive field size exceeded the dendritic field size.Radial sections of the retinas with labeled cells were incubated in antisera to reveal the putative transmitters GABA, serotonin, neurotensin, met‐enkephalin and glucagon. No immunoreactivity with these antisera was dete

ISSN:0092-7317    

DOI:10.1002/cne.902730202

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe distribution of the neuropeptide calcitonin gene‐related peptide (CGRP) was studied in relation to the known subcortical somatosensory pathways and contiguous systems in the central nervous system (CNS) of rats by using peroxidase histochemical methods in order to relate zones of immunoreactivity (IR) to cytoarchitecture. CGRP is the most ubiquitous peptide found to date in sensory ganglion cells: principally small and medium‐size neurons emitting thin axons inferred to be largely nociceptive in function on the basis of the peripheral distribution of their terminals. Its apparent absence in sympathetic axons provides an especially useful sensory marker.The distribution of CGRP‐IR axons displays remarkable selectivity at each level of the CNS. The trigeminal root distributes axons primarily to the pericornual layers (laminae I and II) of spinal V nucleus caudalis and to subnucleus oralis, evading the subnucleus interpolaris and contributing only few axons to principal V. Although there are only a few CGRP‐IR somata at each level, heavily labeled axon trajectories can be traced to the nuclei of the solitary tract, the parabrachial nuclei, several sectors of the caudal medial thalamus, and the central nucleus of the amygdala. A sector of labeled neuron somata lies contiguous to each of these axon terminal zones, the largest of which is a thalamic nucleus containing cells of distinctive dendritic architecture extending from the periaqueductal gray across the posterior group nuclei to the peripeduncular nucleus, forming a linear array at the mesodiencephalic junction.The relation of CGRP‐IR axonal distribution to spinothalamic, visceral, and gustatory systems is discussed in the context of a specialized „chemosensory”︁ component of the thin‐fiber som

ISSN:0092-7317    

DOI:10.1002/cne.902730203

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

年代:1988

数据来源: WILEY

摘要:

AbstractUsing an antiserum against conjugated histamine we mapped the histaminergic somata and their fiber projection areas in carbodiimide‐fixed guinea pig central nervous system. The neurons were large and they were found exclusively in the posterior hypothalamus, as in the rat, but in the guinea pig they were more numerous and distributed more widely in a thin layer around the posterior mammillary nucleus, scattered between and within the medial mammillary nuclei, and in a dense cell cluster emerging from the caudal magnocellular nucleus and extending to the medial preoptic area.The density of histamine‐immunopositive fibers was very high in the olfactory tubercle, diagonal band of Broca, nucleus accumbens, medial and cortical amygdaloid nuclei, periventricular and lateral basal hypothalamus, paraventricular thalamus, and in a region from the medial central gray to the locus coeruleus and the parabrachial nucleus. Dense fiber networks were found in the piriform and entorhinal cortex, septum, dentate gyrus, and subiculum, in most parts of amygdala, and in many areas of the hypothalamus, thalamus, substantia nigra, raphe nuclei, inferior olivary, solitary tract and medial vestibular nuclei, and neurohypophysis. Medium fiber density was observed in the internal layers of the olfactory bulb, anterior olfactory nuclei, neocortex, zone CA1 of hippocampus, and many midbrain and hindbrainregions. Low density was present in the outer layers of the olfactory bulb, other parts of hippocampus, the globus pallidus, most of the caudatus‐putamen, the cerebellar cortex, and the dorsal horn of the spinal cord. The retina and most of the myelinated white matter had single or no histaminergic fibers.It may be concluded from the results that most fibers seem to follow a ventromedial route to the forebrain, reaching the amygdala ventral to the medial forebrain bundle, the hippocampus via subiculum, and the hindbrain structures via the medial central gray. As compared to the rat, the fiber projections in the guinea pig brain were denser, particularly in the hippocampus, thalamus, pons‐medulla, and neurohypophysis. The fiber densities in various regions of the guinea pig brain are compared to histamine receptor densities and the possible functions of histamine are di

ISSN:0092-7317    

DOI:10.1002/cne.902730204

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

年代:1988

数据来源: WILEY

摘要:

AbstractDescending projections to the medulla oblongata and rostral medulla spinalis have been examined in the urodeleSalamandra salamandrawith retrograde horseradish peroxidase tracing. Ipsilateral projections originate from the striatum and the nucleus ventrolateralis thalami and reach the medulla oblongata. The ipsilateral nucleus praeopticus magnocellularis reaches the medulla spinalis. The rostral part of the nucleus tuberculi posterioris projects to the ipsilateral medulla oblongata; its caudal part projects further caudally. Tectal efferents and the efferents of the nucleus praetectalis profundus project bilaterally, the nucleus praetectalis superficialis, nucleus mesencephalicus nervi trigemini, torus semicircularis, nucleus Darkschewitsch, and nucleus fasciculi longitudinalis medialis project ipsilaterally to the medulla oblongata. The nucleus mesencephalicus nervi trigemini, nucleus fasciculi longitudinalis medialis, and tectal efferents reach the rostral medulla spinalis. The nucleus ruber projects mainly via the contralateral dorsolateral funiculus to the medulla spinalis. A largely crossed medullary projection arises in the nucleus dorsalis tegmenti pars anterior, a bilateral projection arises in the nucleus dorsalis tegmenti pars posterior, and an ipsilateral projection arises in the nucleus ventralis tegmenti pars anterior. Cerebellar and statoacoustic efferents descend to the medulla spinalis. The nucleus reticularis isthmi, superior, medius and inferior as well as the nucleus raphes exhibit spinal trajectories. The nucleus vestibularis magnocellularis projects bilaterally, the nucleus vestibularis medialis projects ipsilaterally spinalward. The supposed nucleus descendens nervi trigemini descends mainly contralaterally. A small spinal projection arises in the nucleus tractus solitarii.The results indicate that salamander brains display elaborate descending connections which are similar to those in other vertebrates despite their scarcely differentiated neuronal cytoarchitecture.

ISSN:0092-7317    

DOI:10.1002/cne.902730205

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

年代:1988

数据来源: WILEY

摘要:

AbstractIn the rat, the subdiaphragmatic vagus nerves (SDX) have five major branches—the right gastric, the left gastric, the coeliac, the accessory coeliac, and the hepatic. Although these branches innervate more than the organs after which they are named, some mediate specific behavioral functions. In addition to the SDX trunk, the central stump of each of these branches was incubated in horseradish peroxidase (HRP) for 6 hours in anesthetized rats. After processing the vagal ganglia, pons, medulla, and upper cervical spinal cord of each preparation, the sections were examined for both retrogradely and anterogradely transported HRP reaction product. When only one nerve had been incubated, retrogradely labeled neurons were confined primarily to the ipsilateral ganglion, medulla, and spinal cord. Within the brain, a few labeled neurons occurred within the nucleus ambiguus (NA) and the reticular formation caudal to the NA, but the vast majority appeared in the dorsal motor nucleus of the vagus (DMX). The axons of most labeled neurons in the NA distributed in the gastric branches; those from cells caudal to the NA, probably distributed in the coeliac branch. Most labeled DMX cells also distributed with the gastric branches. Those on the lateral tip of the right DMX, however, had axons in the coeliac branch; those on the left DMX tip, in the accessory coeliac. After incubation of the SDX trunk, anterograde HRP reaction product occurred in the caudomedial nucleus of the solitary tract (NST) just rostral and subjacent to the area postrema (AP). Unlike the retrograde label, anterograde reaction product was bilateral, but always weaker contralaterally. Within the SDX distribution, the afferent axons from the gastric branches exhibited one pattern of termination; those from the coeliac, accessory coeliac, and hepatic branches, another. The gastric branch distributions began dorsolaterally in the SDX termination zone and continued caudally beneath the AP. Immediately subjacent to the AP, gastric branch terminals were never dense and the entire distribution faded at the level of the obex. The coeliac and accessory coeliac distributions began dorsomedially within the SDX termination zone and intensified caudally in a thin band immediately subjacent to the AP. The densest label was associated with the caudal half of the AP, but the distribution thinned rapidly caudal to the obex. The hepatic distribution was similar to that of the coeliac branches but never achieved similar density. Physiological and behavioral data correlate with the anatomical picture in that the efferent functions appear to be more densely localized than the afferent function

ISSN:0092-7317    

DOI:10.1002/cne.902730206

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

年代:1988

数据来源: WILEY

摘要:

AbstractCatecholaminergic neurons in the ventrolateral medulla (VLM) and nucleus of the solitary tract (NTS) are important because of their presumed roles in autonomic regulation, including the tonic and reflex control of arterial pressure, neuroendocrine functions, and the chemosensitivity associated with the ventral medullary surface. However, little is known about the connections of these neurons in the human brain. As a first step in analyzing the functional biochemical anatomy of catecholamine neurons in the human, we used antisera against tyrosine hydroxylase (TH) and phenylethanolamine N‐methyltransferase (PNMT) to localize medullary catecholamine‐containing neurons and processes in the VLM and the NTS.Cells staining for TH were located throughout the VLM. Most cells staining for TH and PNMT, which are therefore adrenergic, occurred in an area of the VLM probably corresponding to the rostroventrolateral reticular nucleus. Axons of TH‐immunoreactive neurons in the VLM projected (1) dorsally, in a series of parallel transtegmental trajectories, toward the dorsomedial reticular formation, the NTS, and vagal motor nucleus, (2) longitudinally, through the central tegmental field, as fascicles running parallel to the neuraxis, (3) ventrolaterally toward the ventral surface (VS) of the rostral VLM where they appeared to terminate, and (4) medially into the raphe, where they arborized. Similar systems of fibers were labeled for PNMT; the longitudinal bundles of PNMT‐labeled axons were limited to the principal tegmental bundle and concentrated dorsally. Fibers containing PNMT were also identified in the medullary raphe, on the medullary ventral surface, and contacting intraparenchymal blood vessels. In the NTS, neurons exhibited immunoreactivity to both TH and PNMT: Four principal subgroups of TH‐immunoreactive neurons were seen: a ventral, an intermediate, a medial, and a dorsal group. Perikarya containing PNMT were restricted to the dorsolateral aspect of the NTS. Processes containing TH and PNMT immunoreactivity were identified in the medial and dorsolateral NTS; others appeared to project between the NTS and the VLM and within the solitary tract.The presence of catecholaminergic fibers of the VLM interconnecting with the NTS, raphe, intraparenchymal microvessels, VS, and possibly the spinal cord suggests that the autonomic and chemoreceptor functions attributed to these neurons also may apply to

ISSN:0092-7317    

DOI:10.1002/cne.902730207

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

年代:1988

数据来源: WILEY

摘要:

AbstractGonadotropin‐releasing‐hormone (GnRH)‐associated peptide (GnRH‐AP) is a 56 amino acid neuropeptide derived from the GnRH prohormone. GnRH‐AP corresponds to the C‐terminal fragment flanking the GnRH peptide. Using an antiserum raised against human GnRH‐AP [1‐56], or against human GnRH, we have investigated the neuronal systems containing either peptide in the central nervous system of the frogRana ridibundaby immunohistological techniques. A main group of GnRH‐AP‐containing perikarya was found in a dorsoventral orientation of the supra anterior preoptic area (SAPA) just in front of the preoptic recess. Fibers originating from these perikarya projected rostrally toward the medial septal nucleus and the diagonal band of Broca. A network of GnRH‐AP‐immunoreactive (ir) fibers runs caudally from the SAPA toward the ventral hypothalamus. A high density of GnRH‐AP‐ir terminals was found in the median eminence. A few positive fibers were detected in the neural lobe of the pituitary, particularly in the region bordering the pars intermedia. Labelling of consecutive sections by either GnRH‐AP or GnRH antibodies showed that GnRH and GnRH‐AP‐like irs were contained in the same cells of the SAPA. The double‐staining technique with electrophoretic elution confirmed the colocalization of GnRH and GnRH‐AP within the same neurons. Such a coexistence indicates that frog GnRH originates from a high molecular weight precursor which is closely related to rat pro‐GnRH. The relative preservation of the C‐terminal sequence of the pro‐GnRH during evolution suggests that GnRH‐AP may possess intrinsic biological activity. The high density of GnRH‐AP‐containing neurons projecting through the external zone of the median eminence would support the concept that GnRH‐AP is involv

ISSN:0092-7317    

DOI:10.1002/cne.902730208

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe oxytocinergic innervation of the brain of the garden dormouse (Eliomys quercinusL.) was studied by means of immunocytochemistry. In contrast to the sparse oxytocin innervation of the rat forebrain, dense fibre networks in various cortical and limbic brain areas were demonstrated in this animal. These include, e.g., the prefrontal cortex, the claustrum, the septum, and the hippocampus. A very dense innervation was also seen in the caudal regions of the garden dormouse brain; these regions are already known to have a relatively dense oxytocin fibre network in the rat.A dense innervation of oxytocin fibres is seen in several brain regions which, in the rat, have oxytocin binding sites but no visible oxytocin innervation. This discrepancy suggests that the differences in the oxytocinergic innervation of these two rodent brains may be due to an oxytocin system in the rat brain that is more difficult to detect immunocytochemically.

ISSN:0092-7317    

DOI:10.1002/cne.902730209

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

年代:1988

数据来源: WILEY

摘要:

AbstractAlthough the basal forebrain, including the globus pallidus, contains a high concentration of gamma‐aminobutyric acid (GABA), it is not known whether all types of neuron in the globus pallidus receive GABAergic synaptic input. We have studied two types of neuron: typical pallidal neurons that project to the subthalamic nucleus and magnocellular neurons which are found in the medial and ventral borders of the globus and project to the sensorimotor cortex.The postembedding immunogold staining of endogenous GABA revealed many preterminal axons and synaptic boutons that contained GABA immunoreactivity. Neurons that projected to the neocortex were postsynaptic to some of the GABA‐immunoreactive boutons, the majority of which formed symmetrical membrane specializations. From a series of random electron micrographs through the perikarya and proximal dendrites of such retrogradely labelled neurons the density of GABA‐containing afferent synaptic boutons was estimated to be 0.58 GABA‐containing boutons per 100 μm of neuronal membrane. The GABA‐containing boutons accounted for 72% of the total afferent input in the proximal regions of the pallidocortical neurons examined. The pallidosubthalamic neurons received many more afferent boutons than did the cortically projecting neurons, a high proportion (80.4%) of which were immunoreactive for GABA. The density of GABA‐containing boutons in contact with pallidosubthalamic neurons was 8.9 boutons per 100 μm.It is concluded that cortically projecting basal forebrain neurons, that are probably cholinergic, are innervated by GABA‐containing afferent boutons. However, pallidosubthalamic neurons in the same part of the basal forebrain are much more densely innervated by GABA‐c

ISSN:0092-7317    

DOI:10.1002/cne.902730210

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

年代:1988

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902730201

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

年代:1988

数据来源: WILEY