bluuebunny/crossref_metadata_2025 huggingface dataset:
NADPH diaphorase (nitric oxide synthase)‐containing nerves in the enteropancreatic innervation: Sources, co‐stored neuropeptides, and pancreatic function
Authors: Kirchgessner A. L. , Liu M.‐T. , Gershon M. D.
Published: January 2005

Pancreatic ganglia are innervated by neurons in the gut and are formed by precursor cells that migrate into the pancreas from the bowel. The innervation of the pancreas, therefore, may be considered an extension of the enteric nervous system. NADPH‐diaphorase is present in a subset of enteric neurons. We investigated the presence of NADPH‐diaphorase in the enteropancreatic innervation, the contribution of extrinsic nerves to the NADPH‐diaphorase‐containing fibers of the gut and pancreas, and the coincident expression of NADPH‐diaphorase in intrinsic neurons of these organs with neuropeptides. The possible role of nitric oxide in the neural regulation of pancreatic secretion was studied in isolated pancreatic lobules. Neuronal perikarya with NADPH‐diaphorase activity were found in both Dogiel type I and type II neurons of the myenteric plexus of the stomach and duodenum. All galanin (GAL)‐immunoreactive neurons and a small subset of vasoactive intestinal polypeptide (VIP)‐ and neuropeptide Y (NPY)‐immunoreactive neurons contained NADPH‐diaphorase activity. NADPH‐diaphorase activity was also found in a subset of VIP and NPY‐immunoreactive pancreatic neurons. Retrograde tracing with FluoroGold established that NADPH‐diaphorase‐containing neurons in the bowel project to the pancreas. NADPH‐diaphorase‐containing fibers were also found to be provided to both organs by neurons in dorsal root ganglia. Secretion of amylase was evoked by L‐arginine. This effect was prevented by NG‐nitro‐L‐arginine (L‐NNA), which also inhibited VIP‐stimulated secretion of amylase; however, L‐NNA had no effect on amylase secretion stimulated by carbachol. These results provide support for the hypo‐thesis that nitric oxide plays a role in the neural regulation of pancreatic secretion. © 1994 Wiley‐Liss, Inc.
Primary olfactory fibres project to the ventral telencephalon and preoptic region in trout (Salmo trutta): A developmental immunocytochemical study
Authors: Becerra Manuela , Manso Maria Jesus , Rodriguez‐Moldes Isabel , Anadón Ramon
Published: January 2005

We studied the development of the primary olfactory system of a teleost, the brown trout, with the aims of clarifying whether the caudal projection pertains to the olfactory or to the terminal nerve system, of identifying the brain regions receiving this projection, and of investigating its possible functional significance. As olfactory markers (OMs) we used two polyclonal antibodies (to substance P and to α‐melanocyte‐stimulating hormone) that were found to label the olfactory projection strongly after preadsortion of the antibody with the corresponding antigen (OMs), and as a terminal nerve marker we used an antiserum to FMRF‐amide peptide. OM labelling was observed in both perikarya and axons of olfactory neurons. In adults, olfactory neurons projected not only to olfactory glomeruli in the olfactory bulb but also, as has been reported previously, to more caudal targets in the forebrain through the medial olfactory tract. Our results show that these targets include the ventral and commissural nuclei of the area ventralis telencephali, the periventricular preoptic region, and the organum vasculosum laminae terminalis. Glomeruli were not observed before hatching, and the extrabulbar olfactory projections appear late in development. Extensive periventricular preoptic olfactory plexuses and olfactory innervation of the organum vasculosum laminae terminalis did not appear until adulthood. The cells of the ganglion nervus terminalis, which form ganglionic groups along the olfactory nerves, were not stained with these olfactory markers at any developmental stage studied, nor was the medial olfactory tract FMRF‐amide peptide immunoreactive. Our results thus confirm the existence of primary olfactory projections to extrabulbar targets in trout. The target regions identified in this study are implicated in sexual behaviour: We discuss the related possibility that, in teleosts, these extrabulbar olfactory projections (rather than projections of the terminal nerve, as is widely held) are the primary mediators of neuroendocrine response to pheromones. © 1994 Wiley‐Liss, Inc.
Expression of the gene for the neuronal intermediate filament protein α‐internexin coincides with the onset of neuronal differentiation in the developing rat nervous system
Authors: Fliegner Karsten H. , Kaplan Michael P. , Wood Teresa L. , Pintar John E. , Liem Ronald K. H.
Published: January 2005

While neurofilaments have long been considered early markers of neuronal differentiation, they cannot be detected in most newly postmitotic neurons of the developing central nervous system (CNS). Here we show that these neurons already express the neuronal intermediate filament protein α‐internexin at high levels. α‐internexin is expressed by most, if not all, neurons as they begin differentiation and shows no overlap with vimentin, whose expression in the CNS is restricted to mitotic neuronal precursors. In the adult, α‐internexin is the only intermediate filament gene expressed by the cerebellar granule cells, the source of the thin‐caliber parallel fibers; conversely, neurofilament proteins are highly expressed in large neurons, which express α‐internexin at low levels. These data suggest that neuronal intermediate filaments may regulate axonal stability and/or diameter through changes not only in their number, but also in their subunit composition. © 1994 Wiley‐Liss, Inc.
Central complex of the primate thalamus: A quantitative analysis of neuronal morphology
Authors: Fénelon Gilles , Yelnik Jérǒme , François Chantal , Percheron Gérard
Published: January 2005

Neuronal morphology was analyzed in the central complex (centre median‐parafascicular complex) of macaques and humans. Cell bodies were described from Nissl material. Golgi‐impregnated dendritic arborizations were reconstructed from serial sections and digitized in three dimensions by computer‐assisted microscopy. The central complex was subdivided into three parts on the basis of cytoarchitectonic and hodological criteria: pars parafascicularis (medial), pars media (intermediate), and pars paralateralis (lateral). The mean cross‐sectional areas of cell bodies were identical (181 μm2) in the three parts in macaques. In humans they were larger in the pars parafascicularis (304 μm2) than in the other parts (248 and 240 μm2).

Small local circuit neurons were found throughout the complex. Large projection neurons differed statistically in the three parts. In macaques, pars parafascicularis neurons had few dendritic stems and tips (3‐11) and a short total dendritic length (2,000 μm). Pars paralateralis neurons had more ramified (5–60) and longer (5,800 μm) dendrites. They bore numerous axonlike processes. Pars media neurons had intermediate characteristics (5–19; 2,400 μm). In humans, pars parafascicular neurons had similar topological characteristics (3–12) but longer dendrites (3,000 μm) than in the monkey. Pars paralateralis neurons had more branched (6–71) and longer (9,000 μm) dendrites, with more numerous axonlike processes. Pars media neurons also had intermediate characteristics (4–25; 3,800 μm). The present study supports a tripartite subdivision of the primate central complex and demonstrates significant interspecies differences. © 1994 Wiley‐Liss, Inc.
Nitric oxide producing neurons in the monkey and human digestive system
Authors: De Giorgio Roberto , Parodi José E. , Brecha Nicholas C. , Brunicardi F. Charles , Becker James M. , Go Vay Liang W. , Sternini Catia
Published: January 2005

Nitric oxide has been proposed as an inhibitory transmitter molecule that plays a role in muscle relaxation and vasodilation in the gastrointestinal tract. The present study analyzes the distribution of nitric‐oxide‐producing neurons in the monkey and human digestive system by means of nicotinamide‐adenine‐dinucleotide‐phosphate‐diaphorase histochemistry. This histochemical method is reliable and convenient for the visualization of neuronal nitric‐oxide synthase, the enzyme responsible for nitric‐oxide generation. In the gastrointestinal tract, nitric‐oxide‐synthase‐related diaphorase activity was present in nerve fibers running through‐out the muscle layer (circular > longitudinal) and in numerous ganglion cells and processes in the myenteric plexus of monkeys and humans. Labelled ganglion cells and fibers also were observed in the submucous plexus, although they were much less numerous than those seen in the myenteric plexus. In the submucosa, a few positive fibers were seen around blood vessels. In the mucosa, stained fibers were sparse at the base of the villi and crypts, whereas they were quite abundant in the muscularis mucosae, especially in the small intestine and colon. In the gallbladder (human), labelling was found in ganglion cells and processes of the innermost and outermost ganglionated plexuses. Stained fibers also were distributed to the muscular layer and, less abundantly, to the mucosa and vasculature. Labelled fibers were more abundant in the sphincter of Oddi (human) than in the gallbladder. In the monkey and human pancreas, nicotinamide‐adenine‐dinucleotide‐diaphorase staining was seen mainly in ganglion cells and fibers of intrapancereatic ganglia, and in processes running among acini, around ducts and in the stroma. A moderate density of stained fibers also was distributed to the vasculature, whereas the islets showed few positive processes. Finally, double label experiments performed in the pancreas showed that the vast majority of neurons producing intric oxide are immunoreactive for vasoactive intestinal peptide.

The present results demonstrate that in the digestive tract of primates nitric‐oxide neurons and processes are widespread. This supports the hypothesis that neural nitric oxide plays a broader role than smooth‐muscle relaxation and vasodilation in the periphery. It may be involved in neuronal communication within the enteric plexuses and may influence different digestive functions including endocrine and exocrine secretions. © 1994 Wiley‐Liss, Inc.
Topographic spinocerebellar mossy fiber projections are maintained in the Lurcher mutant
Authors: Vogel Michael W. , Prittle Jennifer
Published: January 2005

A variety of recent studies of cerebellar development have focused attention on the role of Purkinje cells as organizing elements for the topography of afferent fiber connectivity in the cerebellum. We have investigated the involvement of Purkinje and granule cells in the maintenance of topographic spinocerebellar mossy fiber projections by analyzing the distribution of spinocerebellar mossy fiber terminals in lurcher(+/Lc) mutant mice. Purkinje cells in the +/Lc mutant degenerate starting after the first week of postnatal development because of an intrinsic genetic defect. The loss of their Purkinje cell targets also results in the death of 90% of the granule cells. We examined the distribution of spinocerebellar mossy fiber terminals in the juvenile and adult +/Lc mutant to determine how the pattern of afferent projections is affected by the loss of Purkinje cells shortly after innervation of the cerebellum. Labeling of spinocerebellar mossy fiber terminals with WGA‐HRP in the P38 and adult +/Lc mutant showed that, despite the loss of almost all Purkinje cells and 90% of the granule cells, spinocerebellar mossy fiber project to the appropriate folia and segregate into relatively normal parasagittal bands. While we cannot rule out the possibility that Purkinje cells may be involved in the initial establishment of topographic maps, our results indicate that Purkinje cells are not necessary for the maintenance of the normal spinocerebellar mossy fiber topographic map. © 1994 Wiley‐Liss, Inc.
Serotoninergic innervation of nonprincipal cells in the cerebral cortex of the lizard Podarcis hispanica
Authors: Martínez‐Guijarro F. J. , Blasco‐Ibáñez J. M. , Freund T. F.
Published: January 2005

The mechanism of serotoninergic transmission in the neo‐ and archicortex of mammals kis complex, including both synaptic and nonsynaptic components, direct actions on principal cells, and indirect effects mediated by GABAergic interneurons. Here we studied the termination pattern and synaptic organization of the serotoninergic afferents in the cerebral cortex of the lizard, Podarcis hispanica, which is considered to correspond in part to the mammalian hippocampal formation, with the aim of unraveling basic, phylogenetically preserved rules in the connectivity of this pathway. We demonstrate that serotoninergic afferents, visualized by immunostaining for serotonin itself, establish multiple synaptic contacts with different subpopulations of nonprincipal cells containing parvalbumin, neuropeptide Y, and opioid peptides. The former two subpopulations contain GABA, whereas the opioid‐ immunoreactive neurons are most likely GABA‐negative cells. Evidence is provided at the electron microscopic level that serotonin‐immunoreactive varicosities establish conventional asymmetric synaptic contacts with their nonprincipal targets, but nonsynaptic varicosities also exist. We conclude that, similarly to mammals, a selective synaptic innervation of nonprincipal, possibly inhibitory, neurons is among the mechanisms of serotoninergic modulation of cerebral cortical activity in the lizard. © 1994 Wiley‐Liss, Inc.
Cellular localization and laminar distribution of NMDAR1 mRNA in the rat cerebral cortex
Authors: Conti Fiorenzo , Minelli Andrea , Molnar Marcherita , Brecha Nicholas C.
Published: January 2005

N‐Methyl‐D‐aspartate (NMDA) receptors, which play a critical role in many cortical functions, are composed of a heteromeric assembly of different subunits: of these, the NMDA receptor subunit 1 (NMDAR1) is a constant component of, and thus an excellent marker for, NMDA receptors. In this study, we have investigated the cellular localization and laminar distribution of NMDAR1 mRNA in the cerebral cortex of adult rats by in situ hybridization histochemistry with a 35S‐labeled cRNA probe. Specificity and background levels were determined in adjacent sections incubated with a 35S‐labeled sense RNA. In sections incubated with the antisense RNA probe, specific hybridization signal was observed in a large number of cells. Some cells, however, did not appear to contain NMDAR1 mRNA. The vast majority of these unlabeled cells were small, suggesting that they are astrocytes or other small nonneuronal cells. Double‐labeling studies with in situ hybridization histochemistry and immunocytochemistry with antibodies to glial fibrillary acidic protein (GFAP) showed that about 95.7% of the GFAP‐positive cells did not express NMDAR1 mRNA, indicating that virtually all astrocytes do not contain this transcript.

A semiquantitative evaluation of cortical neurons, defined as those cells larger than the GFAP‐positive astrocytes, revealed that about 80% were associated with silver grains. The number of silver grains associated with every neuron was determined from sections exposed for 15 days, the background level was subtracted, and all labeled neurons were grouped into five groups: A (≤10 grains), B (11–20 grains), C (21–30 grains), and E (>40 grains). The number of neurons belonging to each group was then evaluated according to their occurrence in each cortical layer. In layer I all labeled neurons were in group A, whereas in layers II–III and V–VI positive neurons were in groups A‐E. In layer IV most neurons were in groups A and B, whereas only a few were in group E.

These observations indicate that (1) virtually all cortical cells containing NMDAR1 mRNA in adult rats are neurons; (2) about 80% of all cortical neurons express NMDAR1 mRNA;and (3) labeled neurons can be divided into several groups on the basis of NMDAR1 mRNA levels expressed, which presumably reflect the number of NMDA receptors. The existence of neurons with a different number of receptors may be a critical factor for determining the physiological effect of NMDA receptor activation. In addition, the differential laminar distribution of neurons with different intensities of hybridization signal suggests that NMDA receptors have a different influence at different stages of cortical processing. © 1994 Wiley‐Liss, Inc.
Topographical relations between ipsilateral cortical afferents and callosal neurons in the second somatic sensory area of cats
Authors: Barbaresi Paolo , Minelli Andrea , Manzoni Tullio
Published: January 2005

Experiments were carried out on the second somatic sensory area (SII) of cats to study (1) the laminar distribution of axon terminals from the ipsilateral first somatic sensory cortex (SI); and (2) the topographical relations between their terminal field and the callosal neurons projecting to the contralateral homotopic cortex. To label simultaneously in SII both ipsilateral cortical afferents and callosal cells, cats were given iontophoretic injections of Phaseolus vulgaris‐leucoagglutinin (PHA‐L) in the forepaw zone of ipsilateral SI, and pressure injections of horseradish peroxidase (HRP) in the same zone of contralateral SII. The possibility that ipsilateral cortical axon terminals synape callosal neurons was investigated with the electron microscope by combining lesion‐induced degeneration with retrograde HRP labelling.

Fibers and terminations immunolabelled with PHA‐L from ipsilateral SI were distributed in SII in a typical patchy pattern and were mostly concentrated in supragranular layers. Labelled fibers formed a very dense plexus in layer III and ramified densely also in layers I and II. Labelled axon terminals were both en passant and single‐stalked boutons. Counts of 8,303 PHA‐L‐labelled terminals of either type showed that 82.40% were in supragranular layers. The highest concentration was in layer III (43.99%), followed by layers II (30.22%) and I (8.09%). The remaining terminals were distributed among layers IV (6.96%), V (4.93%), and VI (5.68%). The same region of SII containing anterogradely labelled axons and terminals also contained numerous neurons retrogradely labelled with HRP from contralateral SII. Callosal projection neurons were pyramidal, dwelt mainly in layer III, and were distributed tangentially in periodic patches. Patches of anterograde and retrograde labelling either interdigitated or overlapped both areally and laminarly. In the zones of overlap, numerous PHA‐L‐labelled axon terminals were seen in close apposition to HRP‐labelled pyramidal cell dendrites. Combined HRP‐electron microscopic degeneration experiments showed that in SII axon terminals from ipsilateral SI form asymmetric synapses with HRP‐labelled dendrites and dendriticc spines pertaining to callosal projection neurons.

These results are discussed in relation to the layering and function of the SI to SII projection, and to the evidence that SII neurons projecting to the homotopic area of the contralateral hemisphere have direct access to the sensory information transmitted from ipsilateral SI. © 1994 Wiley‐Liss, Inc.
Pedunculopontine nucleus in the squirrel monkey: Projections to the basal ganglia as revealed by anterograde tract‐tracing methods
Authors: Lavoie Brigitte , Parent André
Published: January 2005

The efferent projections of the pedunculopontine nucleus (PPN) to the ganglia have been studied in the squirrel monkey (Saimiri sciureus) with [3H]leucine andPhaseolus vulgaris‐leucoagglutinin (PHA‐L) as anterograde tracers. Following unilateral injections of [3H]leucine or PHA‐L in the central portion of the PPN, numerous autoradiographic linear profiles or PHA‐L‐labeled fibers ascend to the forebrain, both ipsilaterally and contralaterally. These fibers form a compact bundle that courses in the central portion of the mesopontine tegmentum. At rostral mesencephalic levels, theis bundle splits into ventromedial and dorsolateral fascicles that arborize in basal ganglia and thalamic nuclei, respectively. The substantia nigra and the subthalamic nucleus are by far the most densely innervated structures of the basal ganglia. In these two nuclei, labeled fibers arborize profusely ipsilaterally and less abundantly contralaterally. The labeled fibers in the substantia nigra are thin and varicose and arborize almost exclusively in the pars compacta, where they closely surround the soma and proximal dendrites of dopaminergic neurons. In the subthalamic nucleus labeled fibers are also thin and appear to contact more than one neuron along their course. Numerous labeled fibers also occur in the pallidal complex, where they arborize most profusely in the internal segment. Several thick, labeled fibers oriented dorsolaterally in the pallidal complex give rise to thinner fibers that closley surround the soma and proximal dendrites of pallidal neurons. Some labeled fibers are also scattered in the striatum. These fibers abound in the peripallidal and ventral portions of the putamen, are more sparsely distributed in the remaining portion of the putamen as well as in the caudate nucleus, and are virtually absent in the ventral striatum. These results reveal that the PPN gives rise to a massive and highly ordered innervation of the basal ganglia in the squirrel monkey. This nucleus may thus act as an important relay in the basal ganglia circuitry in primates. © 1994 Wiley‐Liss, Inc.
Intergeniculate leaflet: An anatomically and functionally distinct subdivision of the lateral geniculate complex
Authors: Moore Robert Y. , Card J. Patrick
Published: January 2005

The intergeniculate leaflet (IGL) in the rat is a distinctive subdivision of the lateral geniculate complex that participates in the regulation of circadian function through its projections to the circadian pacemaker, the suprachiasmatic nucleus (SCN) of the hypothalamus. The present investigation was undertaken to provide a precise definition of the IGL and a characterization of its neuronal organization including neuronal morphology, chemical phenotype, connections, and synaptic organization. The IGL extends the entire rostrocaudal lenght of the geniculate complex and contains a distinct population of small to medium neurons. In Golgi preparations, the neurons are multipolar with dendrites largely confined to the IGL. The neurons can be subdivided into three groups on the basis of neurotransmitter content and projections: (1) neurons that contain GABA and neuropeptide Y and project to the SCN; (2) neurons that contain GABA and enkephalin and project to the contralateral IGL; and (3) a small group of neurons that projects to the SCN but not characterized as yet by neurotransmitter content. The IGL receives dense, bilateral input from retinal ganglion cells and dense substance P input of unknown origin. A number of neurons in the anterior hypothalamic area and, particualrly, the retrochiasmatic area project to the IGL, and there are sparse projections from brainstem monoamine and cholinergic neurons. The synaptic organization of the IGL is complex with afferents terminating in glomerular complexes that include axoaxonic synapatic interactions. Virtually all IGL afferents synapse upon dendrites and spines, with the densest synaptic input occurring on the distal portions of the dendritic arbor. The organization of the IGL and its connections as revealed in this analysis is in accord with its role in the integration of visual input with other information to provide feedback regulation of the SCN integration of visual input with other information to provide feedback regulation of the SCN pacemaker. © 1994 Wiley‐Liss, Inc.
Light and electron microscopic immunocytochemical localization of AMPA‐selective glutamate receptors in the rat spinal cord
Authors: Tachibana Masayoshi , Wenthold Robert J. , Morioka Hiroyuki , Petralia Ronald S.
Published: January 2005

α‐Amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionate (AMPA)‐type glutamate receptors are probably the most widespread excitatory neurotransmitter receptors of the central nervous system, and they play a role in most normal and pathological neural activities. However, previous detailed studies of AMPA subunit distribution have been limited mainly to the brain. Thus, a comprehensive study of AMPA receptor subunit distribution was carried out on sections of rat spinal cord and dorsal root ganglia, which were immunolabeled with antibodies made against peptides corresponding to C‐terminal portions of the AMPA receptor subunits: GluR1, GluR2/3, and GluR4. In the spinal cord. Labeling was most prominent in the superficial dorsal horn, motoneurons, and nuclei containing preganglionic autonomic neurons. Immunostaining also was observed in neurons in other regions including those known to contain Renshaw cells and Ia Inhibitory cells. Although overall immunostaining was lighter with antibody to GluR1 than with GluR2/3 and 4, there were neurons were neurons that preferentially stained with antibody to GluR1. These “GluR1 intense” neurons were usually fusiform and most concentrated in lamina X. In dorsal root ganglia, immunostaining of ganglion cell bodies was moderate to dense with antibody to GluR2/3 and light to moderate with antibody to GluR4. Possible neuroglia in the spinal cord (mainly GluR2/3 and 4) and satellite cells in dorsal root ganglia (GliR4) were immunostained. Electron microscopic studies of the the superficial dorsal horn and lateral motor column showed staining that was restricted mainly to postsynaptic densities and associated dendritic and cell body cytoplasm. In dorsal horn, colocalization of dense‐cored vesicles with clear, round synaptic vesicles was observed in unstained presynaptic terminals apposed to stained postsynaptic densities. Subsynaptic dense bodies (Taxi‐bodies) were associated with some stained postsynaptic densities in the superficial dorsal horn and lateral motor column. Based on several morphological features including vesicle structure and presence of Taxi‐bodies, it is likely that at least some of the postsynaptic staining seen in this study is apposed to glutamatergic input from primary sensory afferent terminals. © 1994 Wiley‐Liss, Inc.
Functional and antigenic maps in the rat cerebellum: Zebrin compartmentation and vibrissal receptive fields in lobule IXa
Authors: Chockkan Vijay , Hawkes Richard
Published: January 2005

The mammalian cerebellum is compartmentalized, both structurally and biochemically, into an array of parasagittal bands. In the adult rat, bands can be shown by immunocytochemical staining of a Purkinje cell subset with the monoclonal antibody antizebrin II. In contrast to the bands revealed by the zebrin II distribution, electrophysiological maps of tactile representations show an apparently quite different organization, a patchwork somatotopy of interwoven small receptive fields. We have compared zebrin II compartmentation with the distribution of vibrissal receptive fields in the dorsal face of lobule IXa. Nine adult rats were studied. Zebrin II immunocytochemistry revealed a zebrin II+ band at the midline (P1+) and three others (P2+, P3+, P4+) arrayed laterally, separated by the P1−, P2−, and P3− bands of unstained Purkinje cells. The only significant source of variability was that P3− was sometimes ill defined, making the P3+ and P4+ difficult to distinguish. Electrophysiological recording in the granular layer of lobule IXa identified two reproducible vibrissal receptive fields on each side of the midline (V1 and V2), with a third, more laterally, identified occasionally (V3). When receptive field maps were constructed and aligned with the zebrin II compartment maps from the same individuals, the V1 receptive field was centered on P1−, V2 on P2−, and V3 on P3−. However, the receptive fields typically extended beyond the P− band into the neighboring P+ to each side. Thus there is a simple, reproducible vibrissal receptive field organization in lobule IXa that bears a constant relationship to the Purkinje cell compartmentation revealed by zebrin II immunocytochemistry. The biochemical parcellation of the cortex may serve to organize the afferent and efferent projection topography and thus to align the sensory and motor maps in the cerebellum. © 1994 Wiley‐Liss, Inc.
NADPH‐Diaphorase in the central nervous system of the larval lamprey (Lampetra planeri)
Authors: Schober Andreas , Malz Cordula R. , Schober Wilfried , Meyer Dietrich L.
Published: January 2005

The distribution of nitric oxide synthase (NOS) in the lamprey brain was studied by using reduced nicotinamide‐adenine‐dinucleotide phosphate (NADPH)‐diaphorase histochemistry to further elucidate the evolution of neurons synthesizing nitric oxide. Intense labeling of fibers and/or neurons was found in portions of the lamprey central nervous system, such as the olfactory system, the pineal organ, the habenular region, the nervus stato‐acousticus (N. VIII), the brainstem, and the spinal cord, and also in the adenohypophysis.

Labeled giant cells located at the floor of the 3rd, and 4th ventricle were recognized as reticulospinal neurons. Mauthner and Müller cells were identified according to morphological criteria. Eight pairs of Müller cells and one pair of Mauthner cells were labeled by NADPH histochemistry.

None of these cells had, as yet, been described to display NOS activity in any vertebrate. The massive staining of these cells and the apparent lack of labeling, e. g., in teleost fishes, may be a histochemical correlate to already known differences of functions served by these cells in different species. In addition, our results suggest that the nitric oxide (NO) system has appeared early in vertebrate evolution. © Wiley‐Liss, Inc.
Information processing within the motor cortex. I. Responses of morphologically identified motor cortical cells to stimulation of the somatosensor cortex
Authors: Kaneko Takeshi , Caria Marcello A. , Asanuma Hiroshi
Published: January 2005

Inputs from the somatosensory cortex to the motor cortex have been proposed to function in learning of motor skills. In an attempt to analyze how these somatosensory inputs were processed in the motor cortex, neurons in the superficial layer of the cat motor cortex were classified into three groups on the basis of synaptic responses elicited by intracortical microstimulation (ICMS) of area 2. ICMS was delivered through seven electrodes implanted in area 2. When ICMS through one of the sevn sites produced a response that was greater than 50% of the response produced by stimulating the seven sites at time, the site was called a “dominant” site. Type I cells were those that had a dominant stimulation site and showed a constant response latency when examined by a double shock test. Type II cells were those that had a dominant site but displayed a variable latency. Type III cells had no dominant site and showed a variable latency. Latency of type I responses was 1.2–2.6 milliseconds, which was much shorter than that of type II and type III responses.

Seventy‐nine neurons in layers II/III of the motor cortex, which responded to ICMS in area 2, were stained by intracellular injection of biocytin. From the presence of an apical dendrite and rich spines on the dendrites, 23 type I, 21 type II, and 15 type III cells were classified as pyramidal cells. Type II pyramidal cells were located more superficially than type I and type III pyramidal cells. On the basis of the absence or sparseness of dendritic spines, three type I and four type II cells in layers II/III were classified as nonpyramidal cells. These cells consisted of five small multipolar cells in layer II and a large multipolar cell and a small bitufted cell in layer III. The remaining 11 cells were not classified because of insufficient staining.

Since type I and type II cells are considered to represent monosynaptic and polysynaptic responses to stimulation of area 2, respectively, information flow from type I cells to more superficially located type II cells is presumed in layers II/III of the motor cortex. Type III responses suggest tye presence of a convergent flow of impulses inside of and/or between areas 2 and 4. © 1994 Wiley‐Liss, Inc.
Cerebellothalamocortical and pallidothalamocortical projections to the primary and supplementary motor cortical areas: A multiple tracing study in macaque monkeys
Authors: Rouiller Eric M. , Liang F. , Babalian A. , Moret V. , Wiesendanger M.
Published: January 2005

The goal of the present study was to clarify whether the primary motor cortex (Ml) and the supplementary motor cortex (SMA) both receive, via the motor thalamus, input from cerebellar and basal ganglia output nuclei. This is the first investigation that explores the problem by direct comparison, in the same animal, of thalamic zones that (1) project to M1 and SMA and (2) receive cerebellar‐nuclear (CN) and pallidal (GP) afferents. These four zones were mapped in two monkeys by means of two retrograde tracers for M1 and SMA injections and of two anterograde tracers for CN and GP injections. All injections were performed under electrophysiological control (microstimulation and multiunit recordings). Injections in cortical areas were restricted to the hand/arm representation; in the SMA, the tracer deposit was within the “SMA‐proper” (or “area F3”) and did not include its rostral extension (“pre‐SMA” or “area F6”). It was found that zones of all four types formed a number of highly complex patches of labeling that were usually not confined to one cytoarchitectonically defined thalamic nucleus. The overlap of clusters of labeled terminals and perikarya was evaluated morphometrically (area measurements) on a number of coronal sections along the anteroposterior extent of the motor thalamus. In line with previous studies, the thalamic territories innervated by CN and GP afferents rarely overlapped. However, zones projecting to M1 and/or to SMA included thalamic regions receiving CN as well as GP projections, providing the first evidence of such overlap from individual animals. The present observations support the previous conclusion from this laboratory (based on transsynaptic labeling) that the SMA receives, apart from its strong pallidal transthalamic input, a CN transthalamic input. These present findings that both M1 and SMA are recipients of transthalamic inputs from GP and CN thus support the concept that a mixed subcortical input consisting of weighted contributions from cerebellum, basal ganglia, substantia nigra, and spinothalamic tract is directed to each functional component of the sensorimotor cortex. © 1994 Wiley‐Liss, Inc.
Correlating gamma‐aminobutyric acidergic circuits and sensory function in the electrosensory lateral line lobe of a gymnotiform fish
Authors: Maler Leonard , Mugnaini Enrico
Published: January 2005

Electric fish generate an electric field, which they sense with cutaneous electroreceptors. Electroreceptors project topographically onto the medullary electrosensory lateral line lobe (ELL). The ELL of gymnotiform electric fish is divided into four segments specialized to detect different aspects of the electrosensory input; it is also laminated with separate laminae devoted to electroreceptive input, interneurons, projection neurons, and feedback input. We have utilized antisera to glutamic acid decarboxylase (GAD) and γ‐aminobutyric acid (GABA) to map the distribution of GABAergic cells and fibers in the ELL of the gymnotiform fish, Apteronotus leptorhynchus.

Six types of GABAergic interneurons are found in ELL: Type 2 granular cells (granular layer) project to pyramidal cells; polymorphic cells (pyramidal cell layer) project to the non‐GABAergic type 1 granular cells; ovoid cells (deep neuropil layer) project bilaterally upon basilar dendrites of pyramidal cells; multipolar cells (deep neuropil layer) project bilaterally, probably to dendrites and neurons within the deep neuropil layer; and neurons of the ventral molecular layer and stellate cells (molecular layer) project to apical dendrites of pyramidal cells. GABAergic bipolar cells in the nucleus praeminentialis, a rhombencephalic structure devoted to feedback in the electrosepsory system, project in relatively diffuse fashion to pyramidal cells.

We hypothesize that the various GABAergic circuits of the ELL can be correlated with specific functions: type 2 granular cells with adaptation, size of receptive field center, and gain; polymorphic cells and type 1 granular cells with regulation of surround inhibition; ovoid cells with common mode rejection; and neurons of the ventral molecular layer with adaptive gain control. The feedback GABAergic input from bipolar cells of n. praeminentialis to pyramidal cells may be part of a searchlight mechanism similar to the one postulated for thalamocortical systems. © 1994, Wiley‐Liss, Inc.
Heterogeneity of GABAA receptor in goldfish retina
Authors: Lin Zheng‐Shi , Yazulla Stephen
Published: January 2005

The possibility of GABAA receptor heterogeneity in goldfish retina was studied with immunocytochemical and biochemical approaches: (1) immunoblotted membrane particulates of goldfish retina with mAb 62‐3G1; (2) immunoprecipitation of the detergent‐solubilized membrane proteins with mAb 62‐3G1 followed by the receptor binding assay; (3) photoaffinity labeling of the membrane particulates with 3H‐flunitrazepam (FNZ) and visualization of the labeled receptors by SDS‐PAGE and fluorography; (4) dry autoradiography of 3H‐muscimol and 3H‐FNZ binding sites on frozen sections. Immunoblots showed that 62‐3G1 reacted with 55–57.5 kDa Mr polypeptides, similar to the muscimol‐binding subunit of the receptor complex in bovine brain; while 3H‐FNZ photoaffinity labeled the 52.5 kDa and 41–43 kDa Mr polypeptides. Immunoprecipitated receptors bound only 3H‐muscimol, not 3H‐FNZ. An attempt to precipitate the 3H‐FNZ photolabeled polypeptides failed. Dry autoradiography showed 3H‐PNZ binding only in the inner plexiform layer (IPL); the binding was enhanced with γ‐aminobutyric acid (GABA) and blocked by clonazepam. In contrast, 3H‐muscimol was bound in both the outer plexiform layer (OPL) and IPL, similar to that observed with 62‐3G1 immunocytochemistry. We suggest that there are two subtypes of GABAA receptor in the goldfish retina: (1) GABAA receptors that are not linked to a benzodiazepine (BZD) receptor are located in the OPL and at amacrine‐to‐amacrine and amacrine‐to‐ganglion cell synapses in the IPL and are recognized by 62‐3G1; (2) GABAA receptors that are linked to a BZD receptor are located only in the IPL, largely at amacrine‐to‐bipolar cell synapses and are not recognized by mAb 62‐3G1. © 1994 Wiley‐Liss, Inc.
Innervation of laryngeal nerve paraganglia: An anterograde tracing and immunohistochemical study in the rat
Authors: Dahlqvist Å. , Neuhuber W. L. , Forsgren S.
Published: January 2005

Carotid body‐like organs, paraganglia, frequently occur in the superior and recurrent laryngeal nerves. The paraganglia are supplied with a rich innervation of unknown origin. In the present study, the origin of the innervation of the paraganglia of the rat was studied with two different techniques. One approach was anterograde tracing of wheat‐germ agglutinin‐horseradish peroxidase after injection into the nodose and jugular ganglia of the vagus and the superior cervical ganglion. The other approach was immunohistochemical staining for neuropeptides after excision of the superior cervical ganglion, or vagotomy. Antisera against neuropeptide Y, vasoactive intestinal polypeptide, and calcitonin gene‐related peptide were utilized. Both the tracing method and calcitonin gene‐related peptide immunohistochemistry after vagotomy showed that the paraganglia receive sensory innervation from the vagal ganglia. No labeling was detected in the paraganglia after injection of wheat‐germ agglutinin‐horseradish peroxidase in the superior cervical ganglion. Excision of this ganglion did not lead to a decrease in the neuropeptide‐Y innervation in the paraganglia, but most of this innervation in the surrounding blood vessels disappeared. The observations show that the superior cervical ganglion does not contribute to the innervation in the paraganglia and that the neuropeptide‐Y innervation of the blood vessels originates from the superior cervical ganglion whereas that of the paraganglia has another origin, most likely local ganglionic cells. The results also suggest that the vasoactive intestinal polypeptide innervation in the paraganglia arises from local ganglionic cells. The two approaches complemented each other in mapping the afferent and efferent nerve supply of the paraganglia. © 1994 Wiley‐Liss, Inc.
Corticothalamic connections of auditory‐related areas of the temporal lobe in the rhesus monkey
Authors: Pandya Deepak N. , Rosene Douglas L. , Doolittle Andrew M.
Published: January 2005

Corticothalamic connections of auditory areas of the superior temporal regions (STR) were investigated in the rhesus monkey. These connections are organized according to the recently described architectonic parcellation of the STR. The core line regions of the supratemporal plane (STP) project to the medial geniculate nucleus (MGN). All regions except the primary auditory area also have projections to additional thalamic nuclei. The rostral STP has strong connections with the caudal part of the ventral subdivision (MGv) of MGN as well as with medial pulvinar (PM). In contrast the primary auditory areaprojects mainly to rostral MGv. The caudalmost STP projects mainly to the dorsal subdivision (MGd) and to the magnocellular subdivision (MGmc) as well as to the PM and the lateral (PL) and oral (PO) pulvinar, nucleus limitans (Li), and mediodorsal (MD) nucleus. The belt line regions of the superior temporal gyrus (STG) project mainly to the pulvinar but also have projections to MGd and MGmc. Specifically, rostral STG projects to the caudal part of PM, to MGmc, and to the suprageniculate (SG) nucleus, whereas caudal STG projects to the rostral part of PM and to PL, PO, MGd, MGmc, SG‐Li and MD nuclei. The root line areas in the circular sulcus of the Sylvian fissure project mainly to MGmc but also to MGd, PM, and SG‐Li nuclei. These connections originate mainly from neurons in cortical layer VI, with some from layer Vb. It is suggested that these connections may be involved in different aspects of auditory information processing. © 1994 Wiley‐Liss, Inc.
Estrogen‐inducible neurotensin immunoreactivity in the preoptic area of the female rat
Authors: Alexander Mark J. , Leeman Susan E.
Published: January 2005

Neurotensin (NT) neurons in the rat preoptic area are implicated in female‐specific regulation of reproduction. Estrogen markedly increases expression of mRNA encoding the neurotensin/neuromedin N (NT/N) precursor in several cell groups of the preoptic area, including the anteroventral periventricular nucleus, periventricular preoptic nucleus, and medial preoptic nucleus. In the present study, immunohistochemistry was performed on tissue from ovariectomized females with or without estradiol treatment to test the hypothesis that increased levels of NT accompany hormonal induction of NT/N mRNA in these cell groups. Since colchicine treatment is required for visualization of NT‐immunoreactive cell bodies, an additional objective of this study was to determine whether colchicine alters expression of NT/N mRNA in this area. Estradiol caused a pronounced increase in the number of NT‐immunoreactive cell bodies in the anteroventral periventricular nucleus, as well as adjacent parts of the periventricular preoptic nucleus and medial preoptic nucleus. In the absence of colchicine, estradiol increased the number of NT‐immunoreactive fibers in these same regions. Surprisingly, NT‐immunoreactive cell bodies with intense staining were abundant in certain parts of the medial preoptic nucleus regardless of hormonal condition. NT‐immunoreactive cell bodies were also numerous in certain regions where NT/N mRNA‐expressing cells are scarce, and in two of these regions, the median preoptic nucleus and vascular organ of the lamina terminalis, estradiol substantially reduced the number of immunoreactive cell bodies. Treatment of ovariectomized females with colchicine induced expression of NT/N mRNA in the same regions where NT‐immunoreactive cell bodies were unexpectedly numerous, thus providing a compelling explanation for the discordant distributions of the mRNA and peptide. Together with previous findings, the present results indicate that increased levels of NT accompany hormonal induction of NT/N mRNA in the anteroventral periventricular nucleus, as well as adjacent parts of the periventricular preoptic nucleus and medial preoptic nucleus. In other regions of the preoptic area, colchicine‐inducible expression of NT/N mRNA confounds assessment of hormonal influences on NT synthesis. Multiple populations of neurons capable of NT synthesis can be distinguished in the rostral preoptic area on the basis of differential responsiveness to estrogen or colchicine, thereby providing additional evidence for functional heterogeneity among NT‐synthesizing neurons in this region. © 1994 Wiley‐Liss, Inc.
A topographically organized gamma‐aminobutyric acid projection from the ventral pallidum to the nucleus accumbens in the rat
Authors: Churchill Lynn , Kalivas Peter W.
Published: January 2005

Anatomical and electrophysiological studies have indicated that a reciprocal projection from the ventral pallidum back to the nucleus accumbens exists and has functional relevance. In this study, the topographical projection from the ventral pallidum to the nucleus accumbens was examined by using retrograde tracing with fluoro‐gold iontophoresed in subcompartments of the nucleus accumbens in rats combined with either in situ hybridization for glutamic acid decarboxylase and preproenkephalin mRNA or substance P immunoreactivity. Deposits made into the medial nucleus accumbens preferentially labeled neurons in the medial ventral pallidum, while deposits into the dorsolateral nucleus accumbens, at or lateral to the anterior commissure, labeled primarily cells in the dorsal and lateral ventral pallidum. A mediolateral to rostrocaudal topography was also observed, with the medial deposits preferentially labeling cells in rostral ventral pallidum and the lateral deposits resulting in retrogradely labeled cells in the ventral pallidum below the crossing of the posterior anterior commissure (subcommissural) as well as below the globus pallidus (sublenticular). The majority of cells retrogradely labeled with fluoro‐gold were double‐labeled for glutamic acid decarboxylase mRNA. In contrast, very few retrogradely labeled neurons in the ventral pallidurn were double labeled for mRNA for preproenkephalin. These data demonstrate a topographically organized projection from the ventral pallidum, to the nucleus accumbens that is primarily γ‐aminobutyric acid (GABA)‐ergic and reciprocal to the GABAergic projection from the nucleus accumbens to the ventral pallidum. © 1994 Wiley‐Liss, Inc.