摘要:

AbstractThis report describes the distribution of tyrosine hydroxylase immunoreactive (TH‐ir) structures in the brain of the goldfish (Carassius auratus). The localization of TH‐ir cell groups revealed by immunocytochemical techniques is largely in accordance with catecholamine distribution previously reported in teleosts by using monoamine fluorescence; however, in the telencephalon and diencephalon, several new cell groups are elucidated. In the telencephalon, TH‐ir cell bodies are observed in the olfactory bulb, area ventralis telencephali, and the central zone of the area dorsalis telencephali. TH‐ir fibers and terminals are moderately dense throughout the telencephalon except for a sparse innervation of the area dorsalis, pars medialis. Immunostained cells are present in the suprachiasmatic nucleus and magnocellular and parvicellular components of the preoptic nucleus. Immunoreactive fibers from preoptic cells can be traced caudally in two main tracts to the infundibulum. Dense immunoreactivity around cells in the pituitary provides anatomical support for catecholamine involvement in the neuroendocrine axis probably via preopticohypophysial connections. At middiencephalic levels, immunoreactive cells are present in the ventral thalamus, nucleus pretectalis periventricularis, pars ventralis, and paraventricular organ pars anterioris. In the caudal diencephalon, TH‐ir cells are seen within the posterior tuberal nuclei and dorsal to posterior recess. No immunostained cells are observed in the midbrain. In the hindbrain, tyrosine hydroxylase containing cells comprise three groups similar to that described using Falck‐Hillarp histofluorescence (Parent et al., ′78), i.e., isthmal, central medullary, and medullospinal groups. Tyrosine hydroxylase immunoreactivity is interpreted as evidence for the presence of catecholamines and not only provides an anatomical basis for the functional significance of catechol amines in teleosts, but may be useful in elucidating homologous structures in tetrapod vertebrates, although certain sites of immunoreactivity may prove to be uniqu

ISSN:0092-7317    

DOI:10.1002/cne.902610102

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe distribution of acetylcholine neurons in the brainstem of the cat was studied by choline acetyltransferase (ChAT) immunohistochemistry and compared to that of catecholamine neurons examined in the same or adjacent sections by tyrosine hydroxylase (TH) immunohistochemistry. The largest group of ChAT‐positive (+) neurons was located in the lateral pontomesencephalic tegmentum within the pedunculopontine tegmental nucleus and the laterodorsal tegmental nucleus rostrally and within the parabrachial nuclei and locus coeruleus nucleus more caudally. TH+ neurons were found to be coextensive and intermingled with ChAT‐h neurons in the dorsolateral pontomesencephalic tegmentum, where the number of ChAT+ cells (approximately 18,500) exceeded that of the TH+ cells (approximately 12,000). In the caudal pons, scattered ChAT+ neurons were situated in the ventrolateral tegmentum together with TH+ neurons. In the medulla, numerous ChAT+ cells were located in the lateral tegmental field, where they extended in a radial column from the dorsal motor nucleus of the vagus to the ventrolateral tegmentum around the facial and ambiguus nuclei, occupying the position of preganglionic parasympathetic neurons of the 7th, 9th, and 10th cranial nerves. TH+ cells were also present in this field. Neurons within the general visceral, special visceral, and somatic motor cranial nerve nuclei were all imrnunoreactive to ChAT. Scattered ChAT+ neurons were also present within the medullary gigantocellular and magnocellular tegmental fields together with a small number of TH+ neurons. Other groups of ChAT+ cells were identified within the periolivary nuclei, parabigeminal nucleus, prepositus hypoglossi nucleus, and the medial and inferior vestibular nuclei. Acetylcholine neurons thus constitute a heterogeneous population of cells in the brainstem, which in addition to including the somatic and visceral efferent systems, comprises many other discrete systems and represents an important component of the brainstem reticular formation. The proximity to and interdigitation with catecholamine neurons within these systems may be of important functional significa

ISSN:0092-7317    

DOI:10.1002/cne.902610103

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThis study describes the cholinergic innervation of chemically defined nonpyramidal neurons in the hilar region of the rat hippocampus. Cholinergic terminals were identified by immunocytochemistry employing a monoclonal antibody against choline acetyltransferase (ChAT), the acetylcholine‐synthesizing enzyme, and the avidin‐biotin‐peroxidase (ABC) technique. Nonpyramidal neurons in the hilar region were characterized by immunostaining with antibodies against glutamate decarboxylase (GAD), the gamma aminobutyric acid (GABA)‐synthesizing enzyme, and somatostatin (SS). The immunoreactivity to these antibodies was detected by using biotinylated secondary antibodies and avidinated ferritin as an electron‐dense marker. This electron microscopic double immunostaining procedure enabled us to demonstrate that immunoperoxidase‐labeled ChAT‐immunoreactive terminals established symmetric synaptic contacts on the ferritin‐labeled GAD‐and SS‐immunoreactive hilar cells.In additional experiments at least some of the GAD‐ and SS‐immunoreactive hilar neurons were further characterized as commissural neurons by retrograde filling with horseradish peroxidase (HRP) following an injection of the tracer into the contralateral hilus. From these triple labeling experiments, we concluded that at least some GABAergic and somatostatin‐containing neurons in the hilar region, which are postsynaptic to cholinergic terminals, project to the contralateral hippocampus. Together with previous studies on the cholinergic innervation of the hippocampus and fascia dentata, our present results thus demonstrate that different types of hippocampal cells, including GABAergic and peptidergic commissural neurons in the hilar region, re

ISSN:0092-7317    

DOI:10.1002/cne.902610104

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe cytoarchitecture and neostriatal projections of the canine prefrontal cortex (PFC) were examined by using Nissl, silver degeneration, autoradiographic, and horseradish peroxidase techniques.Cytoarchitectonically, the PFC can be divided into six major gyral areas, with each area corresponding to one of the major gyri–proreal, polar, pregenual, subproreal, paraorbital, and orbital–defined myeloarchitectonically by Kreiner (J. Comp. Neurol. 116:117–133, ′61). Of the six major areas, only the proreal gyrus displays a distinctly granular layer IV. In all other gyri, layer IV is more difficult to distinguish. In both the orbital and polar gyri, layer IV is poorly defined and consists of scattered clusters of small cells between layers III and V. In the pregenual, subproreal, and paraorbital gyri, layer IV is not detectable. In all gyri, layer V consists of a thin lamina of small and medium‐size pyramidal cells. The transition from layer HI to layer V is marked by changes in cell density and size as well as staining intensity. Borders between layers V and VI are generally less distinct than those between layers III and V, with the exception of the pregenual gyrus, in which layer V is separated from layer VI by a distinct cell‐poor lamina. In the subproreal and paraorbital gyri, the border between the underlying white matter and layer VI is particularly distinct, with large numbers of neurons oriented tangentially to the white matter. In contrast, the border between layer VI of the orbital gyrus and the white matter is less distinct and consists of palisades of neurons extending well into the white matter.The silver degeneration and autoradiographic methods revealed that prefrontostriatal projections terminate as dorsoventrally oriented longitudinal bands within the medial half of the head and body of the caudate nucleus. Projections from the polar and dorsal proreal gyri terminate most medially in the nucleus while projections from the lateral part of the proreal, subproreal, orbital, and paraorbital gyri terminate progressively more laterally within the medial half of the nucleus. There is apparent overlap between adjacent projection fields. A sparse projection was also noted to a small part of the putamen adjacent to the internal capsule.Injections of horseradish peroxidase into the medial and ventromedial parts of the head of the caudate nucleus resulted in widespread retrograde labeling in parts of the proreal, pregenual, paraorbital, subproreal, and central precruciate gyri. Labeled neurons were located primarily in the superficial part of layer V with smaller numbers of labeled cells in layers III, IV, and VI.These results indicate that the PFC in the dog can be divided into several Cytoarchitectonically distinct gyri that project topographically and with some degree of overlap to the medial part of the head and body of the caudate nucleus. Data from other studios in the cat show that the medial part of the caudate nucleus receives preferential projections from prelimbic and infralimbic cortical regions as well as from the basolateral amygdaloid nucleus. These findings, combined with those reported in the present study, indicate that the medial part of the carnivore caudate nucleus may be closely associated with limb

ISSN:0092-7317    

DOI:10.1002/cne.902610105

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractOuabain‐sensitive, K+‐dependent p‐nitrophenylphosphatase (K+‐pNPPase) activity, which represents the second dephosphorylation step of Na+, K+‐ATPase, was localized histochemically at the light and electron microscopical levels in the goldfish retina. K+‐pNPPase staining was most intense in the outer and inner plexiform layers and less intense over the photoreceptor inner segments. K+‐pNPPase staining was observed on the membranes of horizontal cell dendrites and presynaptic membrane of all cone pedicles but only rarely over rod spherules. Bipolar cell dendrites in the outer plexiform layer were not stained for K+‐pNPPase. In the inner plexiform layer (IPL), K+‐pNPPase staining was observed at 90% of the bipolar cell ribbon synapses but only at 40% of amacrine cell synapses. The proportion of K+‐pNPPase staining at amacrine cell synapses increased from 26 to 49% as one progressed from the outer to inner layers of the IPL, while staining at bipolar cell synapses showed no such trend. Only 16% of the amacrine synapses onto mixed, rod‐cone (mb) bipolar cell synaptic terminals were positive for K+‐pNPPase. We suggest that the differential distribution of K+‐pNPPase staining at retinal synapses can be explained, in part, by the ionic conductances gated at the postsynaptic sites. In addition, the presence of K+‐pNPPase on lateral horizontal cell dendrites in cone pedicles is consistent with the hypothesis that the sodium pump is involved in the release of GABA at feedback synapses from horizontal ce

ISSN:0092-7317    

DOI:10.1002/cne.902610106

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractIn primary visual cortex of hooded rats, pyramidal cells in layer V may be classified as long, medium, or short, on the basis of the layer in which the apical dendrite terminates. The present study determines which of these types of pyramidal cells project to the superior colliculus. Two different strategies were used to label corticotectal cells with horseradish peroxidase (HRP). In the first set of experiments, a large number of corticotectal cells were labeled by retrograde transport following injection of HRP into the superior colliculus. In the second set of experiments, single unit recording was used to identify corticotectal cells physiologically by antidromic activation from the superior colliculus. These cells were then impaled and labeled by intracellular iontophoresis of HRP. The results from both techniques suggest that only long pyramidal cells send an axon to the superior colliculus. These cells are distinguished by an apical dendrite that extends into layer I. We conclude that in hooded rats corticotectal cells in primary visual cortex are the long pyramids in layer V.

ISSN:0092-7317    

DOI:10.1002/cne.902610107

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe aim of this study was to examine the growth of fine‐diameter, Aδ and C, primary afferents into the dorsal horn of the spinal cord. To do this, Aδ and C primary afferents were transganglionically labeled with wheat germ agglutinin‐horseradish peroxidase (WGA–HRP) in fetal rats at various ages and their growth was traced into the lumbar spinal cord. Sciatic or common peroneal nerves were injected with WGA–HRP at E18–E21.5 (just before birth) and the fetuses were returned to the uterus for 24 h before histochemical analysis. The results show fine‐diameter afferent fibers growing into the L4/L5 spinal cord at E19 when they reach the white matter overlying the dorsal horn and begin to penetrate lamina I. Twelve hours later at E19.5 terminals can be seen in lamina IIo and by E20 they are increasing in density and have reached Hi. By birth they have achieved the density in laminae I and II that is found in the neonate and young rat. Labeling of only the peroneal branch of the sciatic nerve, leaving the tibial unlabeled, demonstrated that the somatotopic specificity of central terminal fields is apparent from the time fine afferent fibers first grow into th

ISSN:0092-7317    

DOI:10.1002/cne.902610108

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe morphology in the dorsal horn of the lumbar spinal cord of the collateral branches and terminal arborizations of three different types of low‐threshold mechanoreceptor innervating the skin of the rat hindlimb has been studied by the intracellular injection of horseradish peroxidase into physiologically characterized afferent fibres. The central terminals of five rapidly adapting glabrous skin mechanoreceptors (RA), six hair follicle afferents (HFA), and four slowly adapting type I afferent fibres (SA I; two from glabrous and two from hairy skin) were recovered for detailed analysis. The number of collaterals per axon varied from eight to 12, and the length of axon stained from 3.5 to 4.7 mm. In each afferent, while the majority (52–67%) of the terminal arborizations displayed extensive branching with large numbers of en passant and terminal synaptic boutons, the arborizations at the caudal and rostral extremes of the terminal field tended to be much simpler and less profuse, with few and in some cases no boutons. This did not appear to be the consequence of inadequate filling.The general pattern of the terminal arborizations was one of mediolaterally compressed, rostrocaudally oriented sheets. In the case of the RA afferents there was no overlap between the adjacent terminal arborizations; a few of the arborizations of the SA I afferents overlapped; most, but not all, of the HFA terminal arborizations overlapped. The terminal arborizations of the HFAs had a distinctive morphology identical to the flame‐shaped arbors described in earlier Golgi studies and included synaptic boutons extending from inner lamina II to lamina IV. The morphologies of the RA and SA terminal arborizations were similar to each other, but the former tended to be concentrated in lamina IV with branches in III and V, whereas the latter tended to V with few branches more superficial than lamina IV. There were also differences in the intercollateral spacing between these two types of afferent fibre.While there are similarities between the morphology of the central terminals of cutaneous low‐threshold mechanoreceptors in the rat and those previously described in the cat (for example, the longitudinally continuous arrangement of the mediolaterally restricted flame‐shaped HFA arborizations and the discontinuous RA arborizations arising from a dorsally located axon), there are also some major differences: the large number of HFA arbors extending to lamina Hi and to lamina IV rather than being restricted to lamina III, the deeper location of the RA arbors (in laminae IV and V rather than lamina III), and the absence of a regular lateral convexity in the collateral axon of the SA type I

ISSN:0092-7317    

DOI:10.1002/cne.902610109

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractIntracellular recording and dye injection were used to study the structure and electrophysiological properties of individual neurons that project to the corpora allata of the cockroach,Diploptera punctata.Neurons in the pars intercerebralis generate long‐duration, tetrodotoxin‐sensitive action potentials. Dye injection revealed two cell types. One type extends axons to the contralateral nervi corporis cardiaci I, some of which innervate the corpora allata, and another type extends a major axon down each of the circum‐oesophageal connectives. Neurons in the pars lateralis also generate long‐duration action potentials. These neurons extend axons to the ipsilateral nervi corporis cardiaci II, which continue on to terminate in the corpora cardiaca and the corpora allata. Small groups of all the above neuronal types are dye and electrically coupled. Penetration and dye injection into nerve terminals in the corpora allata and corpora cardiaca confirmed the innervation of the corpora allata by neurons located in the pars intercerebralis and pars laterally and revealed a third class of neurons that have terminals in the corpora allata: intrinsic neurons of the corpora c

ISSN:0092-7317    

DOI:10.1002/cne.902610110

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractSingle unmyelinated sensory afferent nerve fibers were recorded in dorsal root filaments in urethane‐anesthetized or in decerebrate‐spinal rats. The peripheral branch of these axons ran in the sural nerve where they were stimulated by tungsten microelectrodes. All action potentials showed the characteristics of single fiber responses with a fixed all or none shape and a fixed latency at a given stimulus strength. In all units, the action potential evoked from a proximal stimulus site collided with the action potential evoked from a distal stimulus site.Of the 44 single units isolated, 17 showed the expected small progressive decrease of latency of the recorded impulse as the stimulus strength at a fixed point on the sural nerve was progressively raised above threshold. However, in 27 units there was an abrupt jump decrease of latency as the stimulus rose above the threshold. The average size of this latency shortening was 2.2 msec, which occurred as the stimulus strength rose a mean 21% above threshold. As the stimulus rose above threshold, 7 fibers showed 3 different fixed latencies and 2 fibers showed 4 fixed latencies. In order to test the possibility that the peripheral nerve contained 2 branches of the same axon with one conducting slower than the other, the peripheral nerve was stimulated at progressively longer conduction distances. As predicted, the difference between the 2 fixed latencies became larger as the conduction distance increased.We discuss 6 possible explanations for the results and conclude they are consistent with the proposals that some fibers branch distal to the dorsal root ganglion and some branches do not establish a functional sensory ending in the periph

ISSN:0092-7317    

DOI:10.1002/cne.902610111

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY