摘要:

AbstractDopamine induces several light adaptive changes in amphibian retina via receptors with D2‐like pharmacology, but the identity of the primary target cells has not been determined. Using a fluorescent probe consisting of a selective D2 antagonist, N‐(p‐aminophenethyl)‐ spiperone (NAPS), derivatized with the fluorophore Bodipy (NAPS‐Bodipy), we identified the distribution of dopamine binding sites in the retina of two amphibians, post‐metamorphicXenopus laevisand larvalAmbystoma tigrinum. Specific labeling was defined as staining that was displaced by D2 selective ligands (eticlopride or sulpiride), but insensitve to D1 selective drugs (SCH 23390), adrenergic catecholamines (epinephrine or norepinephrine), or serotoninergic analogues (ketanserin). Both rod and cone cells showed specific dopamine D2‐like binding sites arranged in clustered arrays on discrete membrane domains of the inner segment. Labeling of photoreceptor outer segments was continuous and was not displaced by competition with D2 selective ligands; this labeling was considered nonspecific. In addition, in both species, clustered binding of the D2‐probe was found on Müller cells and on a subset of inner retinal cells with the morphology of amacrine/interplexiform cells. Our data provide direct evidence for D2 receptors on both rods and cones, and suggest that the receptors may be clustered into patches within a discrete cellular domain, the inner segment. © 199

ISSN:0092-7317    

DOI:10.1002/cne.903310202

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

年代:1993

数据来源: WILEY

摘要:

AbstractSacral preganglionic neurons are essential to the neural control of the excretory and sex organs. Previously employed multi‐cell tracing methods have certain limitations in the precise morphological analysis of the neural pathways that control these organs. These limitations were overcome by the intracellular injection of neurobiotin or horseradish peroxidase into single preganglionic neurons in the lateral sacral parasympathetic nucleus of the cat. Following light microscopic examination, these neurons, as a group, were found to have an average of five stem dendrites, which divided into 15 dendritic end‐branches that were distributed among eight dendritic terminal fields. These dendrites had a major transverse orientation and were quite long, many of them reaching well into the dorsal and ventral horns and into the dorsal gray commissure. These dendrites also exhibited a major longitudinal orientation, extending an average of 869 μm (combined length of rostral and caudal dendrites) within the nucleus. Two groups of cells emerged on the basis of different dendritic patterns. Cells classed as Type I had dendrites in lamina I and in the ventral horn but lacked a significant projection into the lateral funiculus. Cells classed as Type II had major dendritic projections into the lateral funiculus but lacked dendrites in lamina I. The diverse dendritic patterns of these two cell types indicate dissimilar afferent control mechanisms and suggest that these preganglionic neurons may innervate different target organs. © 1993 Wiley‐Li

ISSN:0092-7317    

DOI:10.1002/cne.903310203

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

年代:1993

数据来源: WILEY

摘要:

Abstractβ‐pigment‐dispersing hormone (β‐PDH) isolated from the fiddler crab (Rao et al., '85) is a member of an octadecapeptide family of neuropeptides common to arthropods. Whereas earlier studies of these peptides in insects were limited to orthopterans, this investigation focuses on dipteran flies. Extracts of heads from the blowflyPhormia terraenovaewere assessed in a fiddler crab bioassay for PDH activity. Immunocytochemistry, dose‐response curves, gel filtration chromatography and reversed‐phase HPLC, combined with bioassay and enzymelinked immunosorbent assay (ELISA), indicate the presence of PDH‐like peptide in the blowfly. Immunocytochemical mapping of PDH‐like immunoreactive (PDHLI) neuroans was performed for the entire nervous systems ofPhormiaand the fruitflyDrosophilawith a β‐PDH antiserum. In the cephalic ganglion (brain, optic lobe and subesophageal ganglion) PDHLI cell bodies could be detected (34 inPhormiaand 16 inDrosophila). In both species, each hemisphere contains 8 PDHLI cell bodies in the optic lobes. These innervate the optic lobe neuropils bilaterally. InPhormia, another set of 8 cell bodies are located in each of the lateral neurosecretory cell groups in the superior protocerebrum. These neurons send axons to the corpora cardiaca‐hypocerebral ganglion complex and to portions of the foregut. In contrast, only the optic lobe neurons display immunoreactivity inDrosophila. Except for the optic lobes, PDHLI processes are distributed only in nonglomerular neuropils of the brain of both species. In the fused thoracico‐abdominal ganglia ofPhormia, 28 PDHLI cell bodies were found (only six were found inDrosophila). In both species, six abdominal PDHLI neurons are efferents with axons innervating the hindgut. We also found that some of the PDHLI neurons in thePhormiabrain and abdominal ganglion contain colocalized FMRFamide‐like immunoreactivity. Since the flies studied here do not display hormonally controlled, fast pigment migrations, the PDH‐like peptide may have a role as neurotransmitter or neuromodulator in the central nervous system, especially in the visual system, and a regulatory role in the stomatogastric system and the hindg

ISSN:0092-7317    

DOI:10.1002/cne.903310204

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

年代:1993

数据来源: WILEY

摘要:

AbstractCalbindin‐D28kis a calcium‐binding protein located in a variety of neuronal cell types in many regions of the central nervous system. In the present study, we describe the distribution of calbindin‐D28k‐immunoreactive cells, fibers, and terminals in the monkey amygdaloid complex. Calbindin‐D28k‐immunoreactive neurons could be divided into four major cell types. Neurons of the first three cell types demonstrated clearly stained dendrites that were either aspiny or had a few spines on their distal portions.Type 1 cellswere small, stellate, or multipolar and found throughout the amygdala.Type 2 cellswere large, multipolar and were most commonly found in the deep nuclei, particularly in the lateral nucleus, intermediate division of the basal nucleus, accessory basal nucleus and in the periamygdaloid cortex.Type 3 cellswere fusiform, of various sizes, and were found throughout the amygdala.Type 4 cellswere quite large and lightly stained; the dendrites of these cells were usually unstained. The size, shape, and location of Type 4 labeled cell bodies suggested that they might be the large, modified pyramidal cells that constitute the projection neurons of the amygdala. Type 4 cells were observed primarily in the lateral, basal, and accessory basal nuclei and in the periamygdaloid cortex. Calbindin‐D28k‐immunoreactive fibers and terminals were difficult to observe in the amygdala partly because of a diffuse, finely granular neuropil labeling that was particularly dense in the anterior cortical and medial nuclei, in the central nucleus, and in the periamygdaloid cortex. The neuropil labeling was substantially lighter in the lateral, basal, and accessory basal nuclei. Conspicuous linear profiles resembling the “calbindin bundles” of the neocortex were evident in large numbers in the accessory basal nucleus, the medial portion of the parvicellular division of the basal nucleus, in the amygdalohippocampal area, and in the periamygdaloid cortex. There were calbindin‐D28k‐positive fibers in the stria terminalis and in the ventral amygdalofugal pathway. When the distributions of calbindin‐D28kand parvalbumin immunoreactivity in the monkey amygdaloid complex were compared, it appeared that the overall distribution of these two calcium‐binding proteins was generally complementary rather than overlapp

ISSN:0092-7317    

DOI:10.1002/cne.903310205

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe distribution of acetylcholinesterase (AChE) was examined in the area dentata of the adult mouse (Mus musculus domesticus). A distinctly stratified distribution of the enzyme was observed and was compared in detail with cytoarchitectural fields and layers. In the stratum moleculare, bands of relatively high AChE activity were seen immediately beneath the pia, at the borders between the outer, middle, and deep portions of the stratum moleculare, and superficial to the granule cell layer. AChE activity was low in the intervening parts of the stratum moleculare. In contrast to the rat, three sublaminae could be discerned in the hilus of the mouse at most septotemporal levels: a limiting subzone, a hilar plexiform layer, and a deep hilar cell mass. Deep to the granule cell layer, AChE activity was high in the limiting subzone and, septally, in the hilar plexiform layer. The deep hilar cell mass stained lightly towards the septal pole of the region but darker at more temporal levels. Numerous AChE‐stained cells were seen in the hilus, with the exception of the most temporal levels. A comparative analysis of the AChE pattern of the area dentata reveals that (1) AChE‐intense supra‐ and infragranular bands are found in all mammals, whereas (2) considerable differences between various strains of mice and between species are seen in the stratum moleculare. The functional significance of the AChE pattern is discussed in relation to species differences and connectivity and also with respect to possible activities of the enzyme other than hydrolysis of ACh, which may be involved in growth‐related functions and in the plastic and degenerative processes observed in Alzheimer's disease. © 1993 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903310206

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

年代:1993

数据来源: WILEY

摘要:

AbstractA combination of [3H]thymidine labelling and retrograde tracing with either horseradish peroxidase (HRP) or true blue (TB) was used to determine whether V primary afferent neurons born on different embryonic (E) days were differentially susceptible to neonatal transection of the infraorbital nerve (ION). In one experiment, rat fetuses were exposed to [3H]thymidine on E‐8.5, 9.5, 10.5, 11.5, 12.5, 13.5, 14.5, or 15.5, the left infraorbital nerve (ION) was transected on the day of birth, and both the regenerate and intact IONs were labelled with HRP when the animals reached adulthood. The percentage of HRP labelled cells that were also heavily labelled by [3H]thymidine was calculated for both the intact ganglion and that ipsilateral to the damaged nerve for each animal. A consistently higher percentage of double labelled cells on the lesioned rather than on the intact side for a given E‐day was taken as an indication that cells born on the day in question had an increased probability of survivalrelativeto the entire population of V ganglion cells that contributed axons to the ION. Cells born late in gestation on E‐12.5 through 14.5 were significantly more likely than early born (E‐9.5 through 11.5) cells to survive neonatal axotomy. In a second experiment, fetuses were exposed to [3H]thymidine on either E‐9.5, E‐10.5, or E‐14.5, the vibrissa pads on both sides of the face were injected with TB within 6 hours of birth, and the ION was transected 6–8 hours later. When these rats reached at least 60 days of age, ganglia were processed for the visualization of both TB and [3H]thymidine labelled neurons. Cells labelled with both tracers would have been born on a given E‐day, projected to the vibrissa pad via the ION at the time of nerve transection, and survived any naturally occurring or lesion‐induced cell death. As in the HRP tracing experiment, ganglion cells born on E‐14.5 were significantly more likely to survive neonatal ION transection than those born on either E‐9.5 or E‐10.

ISSN:0092-7317    

DOI:10.1002/cne.903310207

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

年代:1993

数据来源: WILEY

摘要:

AbstractBushy cells in the anteroventral cochlear nucleus (AVCN) receive their principal excitatory input from the auditory nerve and are the primary source of excitatory input to more centrally located brainstem auditory nuclei. Despite this pivotal position in the auditory pathway, details of the basic physiological information being carried by axons of these cells and their projections to more central auditory nuclei have not been fully explored.In an attempt to clarify these details, we have physiologically characterized and anatomically labeled individual axons of the spherical bushy cell (SBC) class of the cat AVCN. The characteristic frequencies (CFs) of our injected SBC population are low, all less than 12 kHz and primarily (83%) less than 3 kHz, while their spontaneous activity is comparatively high (mean of 59 spikes/sec). In response to short tone bursts at CF, low CF (<1 kHz) SBC units can phase‐lock better than auditory nerve fibers. SBCs with CFs above 1 kHz have primary‐like responses at all stimulus levels and can show robust phase‐locking to an off‐CF, 500 Hz tone. When compared with our previously reported population of labeled globular bushy cells (GBC; Smith et al., 1991,J. Comp. Neurol. 304:387–407), some similarities and differences are apparent in both physiological response properties and axonal projection pattern. GBCs show no low frequency bias in CFs, have lower spontaneous rates, and the high CF units exhibit a primary‐like‐with‐notch response at high stimulus levels as a consequence of a very well timed onset component. Low CF, GBC short tone responses are indistinguishable from those of SBCs. Anatomically, the axons of SBCs cross the midline in the dorsal component of the trapezoid body and typically innervate the medial superior olive (MSO) on both sides, the ipsilateral lateral superior olive (LSO), and the contralateral ventral nucleus of the lateral lemniscus (VNLL). The projections to the contralateral, but not the ipsilateral MSO, show a rostral to caudal delay line configuration, similar to the scheme first proposed by Jeffress (1948,J. Comp. Neurol. 41:35–39). The form of this delay line is consistent with the topographic map of interaural time delays reported by Yin and Chan (1990,J. Comp. Neurol. 64:465–488.). Projections to the ipsilateral LSO often take an indirect route. In contrast, GBC axons travel in the ventral component of the trapezoid body, never innervate the MSO, rarely innervate the ipsilateral LSO, and always innervate the contralateral medial nucleus of the trapezoid body. The terminal specializations of both SBC and GBC axons contain round vesicles. ©

ISSN:0092-7317    

DOI:10.1002/cne.903310208

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe aim of the present study is to provide a complete description of the distribution of choline acetyltransferase (ChAT) immunoreactivity (i) in the brain of the lizardGallotia galloti, on the basis of two different primary antisera: rat anti‐ChAT and rabbit anti‐chicken ChAT. Considering that the brain is a segmented structure, we have analysed our data with respect to transverse segmental domains (or neuromeres), which have been previously described by several authors in the brain of vertebrates.In the telencephalon, ChATi neurons are seen in the cortex, anterior dorsal ventricular ridge, basal ganglia, diagonal band, and bed nucleus of the stria terminalis. Further caudally, ChATi cell bodies are located in the preoptic area, hypothalamus, habenula, isthmus, and all motor efferent centers of the brainstem and spinal cord.Plexuses of ChATi fibers are observed in the areas containing cholinergic cell bodies. In addition, distinct plexuses are found in the cortex, the posterior dorsal ventricular ridge, the neuropiles of all primary visual centers of the diencephalon and mesencephalon, and several non‐visual nuclei of the brainstem.The distribution of ChAT immunoreactivity in the brain ofG. gallotiresembles in many respects that of other vertebrates, and differences are mainly observed in the pretectum and midbrain tectum. Transverse segmental domains were identified in the brainstem and forebrain ofGallotiawhen the cranial nerve roots and fiber tracts were used as a reference, and most cranial motor nuclei were found to occupy the same segmental positions as have been reported in the chick. © 1993 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903310209

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe mammalian neostriatum is divisible into neurochemically and cytoarchitectonically distinct striosome and matrix compartments. This compartmentalization is respected by many afferent and efferent projections of the striatum. The distribution of distinct types of neuroactive substances and receptors and the unique connections of the striosome and matrix suggest a functional segregation between these compartments. The present study examines the organization of efferent projections from each of the striatal compartments to the entopeduncular nucleus (EPN), a major output cente of the basal ganglia.The fluorescent retrograde tracer fluorogold, or rhodamine‐conjugated dextran, was injected into the lateral habenula or the ventrolateral nucleus of the thalamus of adult Wistar rats to identify the topographical organization of EPN‐habenular and EPN‐thalamic neurons. Fluorogold was then placed into the rostral or caudal parts of the EPN, identified from the previous experiment as areas containing predominantly EPN‐habenular or EPN‐thalamic neurons, respectively. Sections containing retrogradely labeled neurons in the neostriatum were simultaneously immunolabeled for calbindin‐D28kDa, a calcium‐binding protein found exclusively in the projection neurons of the matrix. The results indicate that the striatal projection to the EPN‐habenular and EPN‐thalamic parts of the EPN originates from striosome and matrix neurons, respectively. The duality of striatal outflow involving the EPN suggests a mechanism whereby the striosome is integrated into subcortical pathways that modulate the activity of the basal ganglia via the ascending serotoninergic projection from the dorsal raphe nucleus, whereas the matrix is involved in a loop that includes the thalamus and the cerebral cortex. © 19

ISSN:0092-7317    

DOI:10.1002/cne.903310210

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

年代:1993

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.903310201

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

年代:1993

数据来源: WILEY