bluuebunny/crossref_metadata_2025 huggingface dataset:
Intra‐amygdaloid projections of the lateral nucleus in the cat: PHA‐L anterograde labeling combined with postembedding GABA and glutamate immunocytochemistry
Authors: Smith Y. , Paré D.
Published: January 2005

Research on the implication of the amygdala in classical fear conditioning suggests that the central amygdaloid nucleus is the output station of the amygdala for conditioned fear responses, while the lateral nucleus acts as the input nucleus, at least for auditory conditioned stimuli. However, the nature and locus of the plastic changes taking place between these two nuclei are unknown partly because the neurotransmitter(s) used by intra‐amygdaloid projections of the lateral nucleus has not been identified. To address this issue in cats, anterograde tracing with Phaseolus vulgaris‐leucoagglutinin (PHA‐L) was combined with postembedding immunocytochemistry for gamma‐aminobutyric acid (GABA) and glutamate.

Two sectors can be recognized in the lateral nucleus of the cat: a shell located laterally along the external capsule, and a core. Iontophoretic injections of PHA‐L in these two sectors revealed that they have nonoverlapping intra‐amygdaloid targets with the exception of a common projection to the central lateral nucleus. The core projects mainly to itself and to the basomedial nucleus, whereas the shell contributes a massive projection to the basolateral nucleus. No projection of the lateral nucleus to the central medial nucleus was found. Electron microscopically, PHA‐L‐labeled axon terminals in the lateral, basomedial, basolateral, and central lateral nuclei as well as in the perirhinal and insular cortices formed asymmetric synapses (100%; n = 289) with dendritic spines (77–100%). Moreover, postembedding immunocytochemistry revealed that PHA‐L‐labeled axon terminals are immunoreactive for glutamate but not GABA.

Since most amygdaloid projections to the brainstem originate in the central medial nucleus, these results suggest that intra‐amygdaloid targets of the lateral nucleus are involved in the transmission of auditory conditioned stimuli to the central medial nucleus. Moreover, these findings imply that intra‐amygdaloid projections of the lateral nucleus use glutamate but not GABA as a neurotransmitter. © 1994 Wiley‐Liss, Inc.
Peripheral innervation patterns of vestibular nerve afferents in the bullfrog utriculus
Authors: Baird R. A. , Schuff N. R.
Published: January 2005

Vestibular nerve afferents innervating the bullfrog utriculus differ in their response dynamics and sensitivity to natural stimulation. They also supply hair cells that differ markedly in hair bundle morphology. To examine the peripheral innervation patterns of individual utricular afferents more closely, afferent fibers were labeled by the extracellular injection of horseradish peroxidase (HRP) into the vestibular nerve after sectioning the vestibular nerve medial to Scarpa's ganglion to allow the degeneration of sympathetic and efferent fibers. The peripheral arborizations of individual afferents were then correlated with the diameters of their parent axons, the regions of the macula they innervate, and the number and type of hair cells they supply.

The utriculus is divided by the striola, a narrow zone of distinctive morphology, into medial and lateral parts. Utricular afferents were classified as striolar or extrastriolar according to the epithelial entrance of their parent axons and the location of their terminal fields. In general, striolar afferents had thicker parent axons, fewer subepithelial bifurcations, larger terminal fields, and more synaptic endings than afferents in extrastriolar regions. Afferents in a juxtastriolar zone, immediately adjacent to the medial striola, had innervation patterns transitional between those in the striola and more peripheral parts of the medial extrastriola. Most afferents innervated only a single macular zone. The terminal fields of striolar afferents, with the notable exception of a few afferents with thin parent axons, were generally confined to one side of the striola.

Hair cells in the bullfrog utriculus have previously been classified into four types based on hair bundle morphology (Lewis and Li: Brain Res. 83:35–50, 1975). Afferents in the extrastriolar and juxtastriolar zones largely or exclusively innervated Type B hair cells, the predominant hair cell type in the utricular macula. Striolar afferents supplied a mixture of four hair cell types, but largely contacted Type B and Type C hair cells, particularly on the outer rows of the medial striola. Afferents supplying more central striolar regions innervated fewer Type B and larger numbers of Type E and Type F hair cells. Striolar afferents with thin parent axons largely supplied Type E hair cells with bulbed kinocilia in the innermost striolar rows. © 1994 Wiley‐Liss, Inc.
Dopaminergic neurons in rat ventral midbrain express brain‐derived neurotrophic factor and neurotrophin‐3 mRNAs
Authors: Seroogy Kim B. , Lundgren Kerstin H. , Tran Tien M. D. , Guthrie Kathleen M. , Isackson Paul J. , Gall Christine M.
Published: January 2005

Studies of the trophic activities of brain‐derived neurotrophic factor and neurotrophin‐3 indicate that both molecules support the survival of a number of different embryonic cell types in culture. We have shown that mRNAs for brain‐derived neurotrophic factor and neurotrophin‐3 are localized to specific ventral mesencephalic regions containing dopaminergic cell bodies, including the substantia nigra and ventral tegmental area. In the present study, in situ hybridization with 35S‐labeled cRNA probes for the neurotrophin mRNAs was combined with neurotoxin lesions or with immunocytochemistry for the catecholamine‐synthesizing enzyme tyrosine hydroxylase to determine whether the dopaminergic neurons, themselves, synthesize the neurotrophins in adult rat midbrain. Following unilateral destruction of the midbrain dopamine cells with 6‐hydroxydopamine, a substantial, but incomplete, depletion of brain‐derived neurotrophic factor and neurotrophin‐3 mRNA‐containing cells was observed in the ipsilateral substantia nigra pars compacta and ventral tegmental area. In other rats, combined in situ hybridization and tyrosine hydroxylase immunocytochemistry demonstrated that the vast majority of the neurotrophin mRNA‐containing neurons in the substantia nigra and ventral tegmental area were tyrosine hydroxylase immunoreactive. Of the total population of tyrosine hydroxylase‐positive cells, double‐labeled neurons constituted 25–50% in the ventral tegmental area and 10–30% in the substantia nigra pars compacta, with the proportion being greater in medial pars compacta. In addition, tyrosine hydroxylase/neurotrophin mRNA coexistence was observed in neurons in other mesencephalic regions including the retrorubral field, interfascicular nucleus, rostral and central linear nuclei, dorsal raphe nucleus, and supramammillary region. The present results demonstrate brain‐derived neurotrophic factor and neurotrophin‐3 expression by adult midbrain dopamine neurons and support the suggestion that these neurotrophins influence dopamine neurons via autocrine or paracrine mechanisms. These data raise the additional possibility that inappropriate expression of the neurotrophins by dopaminergic neurons could contribute to the neuropathology of disease states such as Parkinson's disease and schizophrenia. © 1994 Wiley‐Liss, Inc.
The lacteridian reticular thalamic nucleus projects topographically upon the dorsal thalamus: Experimental study in Gallotia galloti
Authors: Díaz Carmen , Yanes Carmen , Trujillo Carmen‐María , Puelles Luis
Published: January 2005

The projection pattern of the ventral thalamic reticular nucleus onto the dorsal thalamus was studied in the lizard Gallotia gallotiusing in vitro horseradish peroxidase and fluorescent carbocyanine labelling techniques. Localized label deposits at three dorsoventrally spaced sites in the dorsal thalamus elicited retrograde transport into separate, though partly overlapping, medial, dorsolateral and ventrolateral sectors within an extended cytoarchitectonic complex which may be globally identifiable as the reticular nucleus. Neurons found in the dorsolateral and ventrolateral sectors mainly corresponded to the cell group named nucleus ventromedialis (or nucleus of the dorsal supraoptic decussation) in the literature, whereas neurons labelled in the medial sector corresponded to the so‐called dorsal hypothalamic nucleus. Sparser cells appear labelled in the superficially placed nucleus suprapeduncularis. Thalamotelencephalic fibers arising from the injected dorsal thalamic nuclei also project on the corresponding retrogradely labeled sectors within the reticular nucleus.

These findings reveal a rough topographic organization in the connections of the extended reticular nucleus complex with the whole dorsal thalamus. This supports the hypothesis of hodological homology between this ventral thalamic formation in Gallotiaand the mammalian thalamic reticular nucleus. © 1994 Wiley‐Liss, Inc.
Presence of growth inhibitors in fish optic nerve myelin: Postinjury changes
Authors: Sivron T. , Schwab M. E. , Schwartz M.
Published: January 2005

This study shows that the fish optic nerve, which is able to regenerate after injury, contains myelin‐associated growth inhibitors similar to the growth inhibitors present in mammalian central nervous system (CNS) myelin. The ability of nerves to regenerate was previously correlated with the ability of sections from these nerves to support neuronal attachment to and axonal growth in vitro. Thus neuroblastoma cells or embryonic neurons became attached to and grew axons on sections of rat sciatic nerve or fish optic nerve, which are spontaneously regenerating systems, but not on sections of rat optic nerve, a nongenerating system. Failure of the latter to support axonal growth has been attributed, at least in part, to growth inhibitors. Recently it was shown that adult neurons, which differ in their growth requirement from embryonic neurons, are unable to extend neurites on sections of normal sciatic nerve but are able to extend neurites on sections of sciatic nerve that was injured prior to its excision. We found a similar in the fish optic nerve, i.e. that the nerve is normally not permissive to growth of adult retinal axons but becomes growth permissive after injury. The nonpermissiveness of the normal fish optic nerve was found to correlate with the presence of myelin‐associated growth‐inhibitory molecules. This inhibitory activity of fish myelin was neutralized by IN‐1 antibodies, known to neutralize rat myelin growth inhibitors apparently similar or even identical to those of rat, but possibly present in lower amounts than in the rat. Results are discussed with respect to the possibility that fish optic nerve, like the rat sciatic regeneration of adult neurons. Such changes might include elimination or neutralization of growth inhibitors. © 1994 Wiley‐Liss, Inc.
Ionotropic glutamate‐receptor gene expression in hypothalamus: Localization of AMPA, kainate, and NMDA receptor RNA with in situ hybridization
Authors: Van Den Pol Anthony N. , Hermans‐Borgmeyer Irm , Hofer Magdalena , Ghosh Prabhat , Heinemann Stephen
Published: January 2005

In situ hybridization and Northern blots were used to study the ionotropic subtypes of the glutamate receptor in the rat hypothalamus. Widespread expression of AMPA, kainate, and NMDA receptor RNA was found in the hypothalamus with the transcripts the same size and number as found in other regions of the brain. Most of the glutamate‐receptor subunits studied were expressed in greater amounts in hippocampus than in hypothalamus; GluR5, on the other hand, showed a greater expression in hypothalamus than in hippocampus. On the basis of Northern blot analysis, all regions of the brain examined, including hypothalamus, cerebral cortex, cerebellum, olfactory bulb, and hippocampus, expressed all eight of the subunits studied. Each subunit showed different relative expressions in the different regions.

In the hypothalamus, GluR1 and GluR2 were among the most widely expressed of the non‐NMDA ionotropic receptors. Other AMPA‐preferring receptors, GluR3 and ‐R4, were also found, but to a lesser extent. Scattered cells expressed the kainate‐preferring receptors GluR5, ‐R6, and ‐R7. The NMDA receptor NMDAR1 was detected throughout the hypothalamus. In many regions of the hypothalamus, only scattered cells showed detectable expression of the glutamate‐receptor mRNA as detected by autoradiographic silver grains over neurons; unlabeled cells were mixed among labeled cells. Every region of the hypothalamus had several different glutamate receptors. The expression of many different types of ionotropic glutamate receptors throughout the hypothalamus suggests that multiple modes of ion channel regulation by glutamate probably operate here and provides further support for the importance of the excitatory transmitter glutamate in hypothalamic regulation. © 1994 Wiley‐Liss, Inc.
Distinct distributions of five NMDA receptor channel subunit mRNAs in the brainstem
Authors: Watanabe Masahiko , Mishina Masayoshi , Inoue Yoshiro
Published: January 2005

The distribution of five NMDA receptor channel subunit mRNAs in the mouse brainstem at postnatal day 21 was semiquantitatively examined by in situ hybridization with subunitspecific oligonucleotide probes. The ∈1 subunit mRNA was observed in various brainstem nuclei. On the other hand, the ∈2 and ∈3 subunit mRNAs were restricted to particular nuclei, and the ∈4 subunit mRNA was detected in several nuclei at very low levels. The dorsal cochlear nucleus exhibited differential expressions of the ∈ subunit mRNAs in distinct neuron types: the ∈2 subunit mRNAin the pyramidal cells, the ∈3 subunit mRNA in the granule cells, and the ∈1 subunit mRNA in other neurons. In the vestibular nuclei, the medial nucleus expressed the ∈1, ∈3, and ∈4 subunit mRNAs, whereas the lateral and superior nuclei expressed the ∈1 subunit mRNA. Such region‐specific expressions were also discerned in the central gray, the superior and inferior colliculi, the medical accessory oculomotor nucleus, the locus ceruleus, the parabrachial nucleus, nucleus of the solitary tract, the caudal subnucleus of the trigeminal spinal tract nucleus, and the inferior olive. In contrast to the differential distributions of the four ∈ subunit mRNAs, intense signals for the ζ1 subunit mRNA were distributed throughout the brainstem. These findings suggest that anatomical organization of the ∈ subunits is heterogeneous in various regions of the brainstem, which would give rise to functional diversity of the NMDA receptor channel in these regions. © 1994 Wiey‐Liss, Inc.
Regulation of retinal ganglion cell axon arbor size by target availability: Mechanisms of compression and expansion of the retinotectal projection
Authors: Xiong Meijuan , Pallas Sarah L. , Lim Steve , Finlay Barbara L.
Published: January 2005

The ability of pre‐ and postsynaptic populations to achieve the proper convergence ratios during development is especially critical in topographically mapped systems such as the retinotectal system. The ratio of retinal ganglion cells to their target cells in the optic tectum can be altered experimentally either by early partial tectal ablation, which results in an orderly compression of near‐normal numbers of retinal projections into a smaller tectal area, or by early monocular enucleation, which results in the expansion of a reduced number of axons in a near‐normal tectal volume. Our previous studies showed that changes in cell death and synaptic density consequent to these manipulations can account for only a minor component of this compensation for the population mismatch.

In this study, we examine other mechanisms of population matching in the hamster retinotectal system. We used an in vitro horseradish peroxidase labeling method to trace individual retinal ganglion cell axons in superior colliculi partially ablated on the day of birth, as well as in colliculi contralateral to a monocular enucleation. We found that individual axon arbors within the partially lesioned tectum occupy a smaller area, with fewer branches and fewer terminal boutons, but preserve a normal bouton denstiy. In contrst, ipsilaterally projecting axon arbors in monoculary enucleated animals occupy a greater area than in the normal condition, with a much larger arbor length and greater number of boutons and branches compared with normal ipsilaterally projecting cells. Alteration of axonal arborization of retinalganglion cells is the main factor responsible for matching the retinal and tectal cell populations within the tectum. This process conserves normal electrophysiological function over a wide range of convergence ratios and may occur through strict selectivity of tectal cells for their normal number of inputs. © 1994 Wiley‐Liss, Inc.
Information processing within the motor cortex. II. Intracortical connections between neurons receiving somatosensory cortical input and motor output neurons of the cortex
Authors: Kaneko Takeshi , Caria Marcello A. , Asanuma Hiroshi
Published: January 2005

Connections between motor cortical neurons receiving somatosensory inputs from area 2 and large pyramidal cells in layer V were examined in the cat via intracellular injection of biocytin and immunohistochemistry of nonphosphorylated neurofilament proteins (npNFP). Biocytin was injected into pyramidal cells in layers II/III of the motor cortex that responded monosynaptically and polysynaptically to microstimulation of the somatosensory cortex and subsequently stained black by the avidin‐biotinylated preoxidase complex method with diaminobenzidine (DAB) and nickel. By using a monoclonal antibody SMI‐32 and a modified peroxidase‐antiperoxidase method with Tris‐aminophenylmethane (TAPM) and p‐cresol as a chromogen, pyramidal cells in layers III and V of the motor cortex were stained red for npNFP. In particular, all the large pyramidal cells in layer V, Betz cells, displayed intense npNFP immunoreactivity not only in the perikarya but also in the dendrites.

Double staining with DAB/nickel and TAPM/p‐cresol showed that biocytin‐filled axon varicosities of the pyramidal cells, which were thought to receive monosynaptic inputs from area 2, made contacts with npNFP‐positive dendrites in layers I‐III around the biocytininjected cell and in layers V‐VI beneath the cell. The present results suggest that the corticocortical input from area 2 to pyramidal cells in layers II/III of the motor cortex is transferred to layer V pyramidal cells, including Betz cells, as well as to neighboring layer II/ III pyramidal cells. Since tetanic stimulation of the somatosensory cortex reportedly produces long‐term potentiation in layer II/III cells of the motor cortex, it seems reasonable to assume that a given area of the somatosensory cortex can produce a long‐lasting change in the activity of a given group of output cells in the motor cortex. © 1994 Wiley‐Liss, Inc.
Distinct spatiotemporal distributions of the N‐Methyl‐D‐aspartate receptor channel subunit mRNAs in the mouse cervical cord
Authors: Watanabe Masahiko , Mishina Masayoshi , Inoue Yoshiro
Published: January 2005

The distribution of five N‐methyl‐D‐aspartate (NMDA) receptor channel subunit mRNAs in the mouse spinal cord from embryonic day 13 (E13) through postnatal day 56 (P56) was semiquantitatively examined at the cervical level via in situ hybridization with subunit‐specific oligonucleotide probes. Signals for the ξ1 subunit mRNA were restricted to the most ventral portion of the spinal cord during embryonic stages. They extended to all laminae of the spinal cord except for the lamina 2 (substantia gelatinosa) during postnatal development. A wide expression of the ϵ2 subunit mRNA was found in the spinal gray matter from E13 through neonatal stages, but the signals became restricted to the lamina 2 by P21. No significant signals for the ϵ3 subunit mRNA were detected in the spinal cord at any developmental stages. The ϵ4 subunit mRNA was distributed widely in the spinal cord during embryonic and early postnatal periods but decreased nearly to background levels by P21. In contrast to the differential distribution of the ϵ subunit mRNAs, the ξ1 subunit mRNA was found ubiquitously at each developmental stage examined. These findings suggest that the molecular organization of the ϵ subunits may be difference between the dorsal horn and the remaining regions in the mature spinal cord, which provides a molecular basis for functional heterogeneity of the NMDA receptor channel. Moreover, this spatial heterogeneity might be generated through drastic alterations in the subunit composition of the channel complex during spinal cord development. © 1994 Wiley‐Liss, Inc.
Ontogeny of catecholamine systems in the central nervous system of anuran amphibians: An immunohistochemical study with antibodies against tyrosine hydroxylase and dopamine
Authors: González Agustín , Marín Oscar , Tuinhof Rienk , Smeets Wilhelmus J. A. J.
Published: January 2005

To get more insight into developmental aspects of catecholamine systems in vertebrates, in particular anuran amphibians, these systems were studied immunohistochemically in embryos and larvae of Xenopus laevis and Rana ridibunda. Antisera against tyrosine hydroxylase (TH) and dopamine (DA) revealed that catecholamine systems are already present at early embryonic stages. The first dopamine group to be detected was found ventral to the central canal of the spinal cord of Xenopus, soon followed by DA cell groups in the posterior tubercle, the hypothalamic periventricular organ, the accompanying cell group of the periventricular organ, and the suprachiasmatic nucleus. Although weakly TH‐immunoreactive cells were found in the olfactory bulb at about the same embryonic stages, DA immunoreactivity was not detected until premetamorphic stage 49. Dopamine cell groups in the caudal brainstem, midbrain, and pretectum appeared at late premetamorphic and prometamorphic stages, whereas the preoptic group was first observed at the metamorphic climax stage. Rana showed an almost similar timetable of development of catecholamine cell groups, except for the caudal brainstem group which was already present at the end of the embryonic period. When compared with previous studies by means of formaldehyde‐induced fluorescence technique, it becomes clear that TH/DA immunohistochemistry enables an earlier detection of catecholamine cell groups and fiber systems in anuran, amphibians. The present study also revealed that the DA‐immunoreactive cells of the hypothalamic periventricular, organ never stained with the TH antiserum during development, thus supporting their putatively DA accumulating nature. Another notable result is the site of origin and rather late appearance of the midbrain dopaminergic cell group. It is, suggested that the latter cell group only partly corresponds to the ventral tegmental area and substantia nigra of amniotes. © 1994 Wiley‐Liss, Inc.
Astrocyte proliferation in the chick auditory brainstem following cochlea removal
Authors: Lurie Diana I. , Rubel Edwin W.
Published: January 2005

Astrocytes in the central nervous system (CNS) respond to injury and disease by proliferating and extending processes. The intermediate filament protein of astrocytes, glial fibrillary acidic protein (GFAP) also increases in astrocytes. These cells are called “reactive astrocytes” and are thought to play a role in CNS repair. We have previously demonstrated rapid increases (< 6 hours) in GFAP‐immunoreactive and silver‐impregnated glial processes in the chick cochlear nucleus, nucleus magnocellularis (NM), following cochlea removal or activity blockade of the eighth nerve. It was not known whether these changes were the result of glial proliferation, glial hypertrophy, or both. The present study examined the time course of astrocyte proliferation in NM following cochlea removal.

Postnatal chicks received unilateral cochlea removal and survived for 6, 12, 18, 24, 36, 48, and 72 hours. Bromodeoxyuridine was used to label proliferating cells. The volume and number of labeled cells in NM was calculated for both the experimental and control sides of the brains for experimental animals was well as for unoperated control animals.

A subset of astrocytes continuously divide in the normal posthatch chick brainstem. The percentage of labeled nuclei increases within NM 36 hours following cochlea removal and is robust by 48 hours. This increase is due to astrocyte proliferation within, rather than migration to, NM. These resulis indicate that rapid increases in GFAP following reduced activity are independent of cell proliferation. The time course of astrocyte proliferation suggests that cellular degeneration within the nucleus may play a role in upregulating astrocyte proliferation. © 1994 Wiley‐Liss, Inc.
Comparative anatomy of serotonin‐like immunoreactive neurons in isopods: Putative homologues in several species
Authors: Thompson Kevin S. J. , Zeidler Martin P. , Bacon Jonathan P.
Published: January 2005

It is now commonly accepted that the arthropod nervous system has evolved only once, and so homologies between crustacean and insect nervous systems can be meaningfully sought. To do this, we have examined the distribution of serotonin (5‐hydroxytryptamine)‐like immunoreactive neurons in the central nervous system (CNS) of four common British isopods. Two species of terrestrial woodlouse, Oniscus asellus and Armadillidium vulgare, the littoral sea slater, Ligia oceanica, and the aquatic water hoglouse, Asellus meridianus, all possess approximately 40 pairs of serotonin‐like immunoreactive neurons, distributed throughout the CNS in a very similar pattern. Interspecific homology is clearly suggested. Serotonin‐like immunoreactive neurons in the first (T1) and fourth (T4) thoracic ganglia are particularly prominent in each of the four species studied. Whole‐mount immunohistochemistry shows that the pair of T1 neurons have large dorsolateral cell bodies and prominent neurites that project medially and then anteriorly, whereas the pair of T4 neurons have ventrolateral cell bodies and neurites that bifurcate to form a thin axon projecting anteriorly to terminate in T3 and a thick medial axon that projects posteriorly into the abdominal neuromeres of the terminal ganglion. Intracellular cobalt staining of these neurons reveals more of their arborizations: The T1 neurons send three processes anteriorly, which arborize in the brain and exit from the CNS via peripheral nerves, whereas the T4 neurons contribute considerably to the extensive pattern of serotonin‐like immunoreactive fibres in T3–T6 ganglia.

The overall pattern of serotonin‐like immunoreactiveneurons in the isopods is similar to that in decapod crustacea, and a number of putative homologies can be assigned. It is more difficult to homologize the isopod serotonin‐like immunoreactive neurons with those in the insect CNS, but some stained brain and thoracic neurons share common cell body positions and axon trajectories in isopods, decapods, and insects and may therefore be homologous. © 1994 Wiley‐Liss, Inc.
Immunocytochemical evidence for the presence of met‐enkephalin and leu‐enkephalin distinct neurons in the brain of the elasmobranch fish Scyliorhinus canicula
Authors: Vallarino Mauro , Bucharles Christine , Facchinetti Fabio , Vaudry Hubert
Published: January 2005

Immunohistochemical methods have been used to investigate the distribution of various opioid peptides derived from mammalian proenkephalin in the central nervous system of Scyliorhinus canicula. The results indicate that both Leu‐ and Met‐enkephalin‐immunoreactive peptides are present in the dogfish brain. In contrast, enkephalin forms similar to Met‐enkephalin‐Arg‐Phe or Met‐enkephalin‐Arg‐Gly‐Leu, and mammalian α‐neo‐endorphin, dynorphin A (1–8), dynorphin A (1–13), and dynorphin A (1–17) were not detected.

Met‐ and Leu‐enkephalin immunoreactivities were found in distinct neurons of the telencephalon and hypothalamus. In particular, cell bodies reacting only with the Met‐enkephalin antiserum were localized in the preoptic nucleus and in the suprachiasmatic region of the hypothalamus. Conversely, cell bodies reacting only with the Leu‐enkephalin antiserum were localized in the pallium and the nucleus lobi lateralis hypothalami. Several areas of the telencephalon and diencephalon exhibited both Met‐ and Leu‐enkephalin‐like immunoreactivity, but the two immunoreactive peptides were clearly contained in distinct perikarya. The overall distribution of Met‐enkephalin‐immunoreactive elements in the dogfish brain exhibited similarities to the distribution of proenkephalin‐derived peptides previously reported for the brain of tetrapods. The fact that Met‐ and Leu‐enkephalin‐like peptides were detected in distinct neurons, together with the absence of dynorphin‐related peptides, suggests the existence of a novel Leu‐enkephalin‐containing precursor in the dogfish brain. © 1994 Wiley‐Liss, Inc.
Comparative distribution of N‐Acetylaspartylglutamate and GAD67 in the cerebellum and precerebellar nuclei of the rat utilizing enhanced carbodiimide fixation and immunohistochemistry
Authors: Moffett John R. , Palkovits Miklos , Namboodiri M. A. Aryan , Neale Joseph H.
Published: January 2005

The most prevalent peptide in the nervous system, N‐acetylaspartylglutamate (NAAG), specifically activates N‐methyl D‐aspartate (NMDA) receptors and a subclass of metabotropic glutamate receptors. One action of this peptide may be to modulate the release of other neurotransmitters, including gamma‐aminobutyric acid (GABA). The present study describes the cellular distribution of NAAG, relative to GABA, in the cerebellum and precerebellar nuclei as a foundation for further physiological investigations. Numerous cells of origin for mossy fibers, including many of the larger neurons of the pontine nuclei, lateral reticular nuclei, vestibular nuclei, reticulotegmental nuclei, and spinal grey, were moderately to strongly stained for NAAG. Many NAAG‐labeled fibers were clearly visible in the cerebellar peduncles and central white matter. Mossy fibers and mossy endings were among the most prominent NAAG‐immunoreactive elements in the cerebellar cortex. Most neurons in the inferior olive were not stained for NAAG, and only sparse, lightly immunoreactive, climbing fiber‐like endings could be identified in restricted regions of the cortical molecular layer. Purkinje neurons ranged from nonreactive to moderately positive, with the great majority being unstained. Cerebellar granule cells did not exhibit any NAAG immunoreactivity. A population of neurons in the deep cerebellar nuclei was highly immunoreactive for NAAG. Additionally, many neurons of the red nucleus were intensely stained for NAAG. Comparisons with staining for the 67 kD form of glutamic acid decarboxylase in serial sections revealed complementary distributions, with NAAG in excitatory pathways and cell groups, and glutamic acid decarboxylase in inhibitory systems. These findings suggest a significant functional involvement of NAAG in the excitatory afferent and efferent projection systems and provide an anatomical basis for investigations into the interactions of NAAG and GABA in the cerebellum. © 1994 Wiley‐Liss, Inc.
Morphology and synaptic connections of slowly adapting periodontal afferent terminals in the trigeminal subnuclei principalis and oralis of the cat
Authors: Bae Yong Chul , Nakagawa Shinji , Yoshida Atsushi , Nagase Yoshitaka , Takemura Motohide , Shigenaga Yoshio
Published: January 2005

Previous studies suggest that sensory information from primary afferent fibers is processed in a distinct manner in the individual subnuclei of trigeminal sensory nuclear complex. The present study has addressed this issue by using intra‐axonal labeling with horseradish peroxidase to examine the ultrastructure and synaptic organization of axon terminals from slowly adapting (SA) periodontal afferents in the ventral subdivision (Vpv) of principalis and the rostro‐dorsomedial part (Vo. r) of oralis. Our observations are based on complete or near‐complete reconstructions of 139 synaptic boutons in Vpv and 105 in Vo. r.

All the labeled boutons contained clear, spherical, synaptic vesicles and were presynaptic to unlabeled dendrites, and they were frequently postsynaptic to unlabeled axon terminals containing pleomorphic synaptic vesicles (P‐endings). The P‐endings frequently formed axodendritic synapses on dendrites which received axodendritic synapses from labeled boutons (synaptic triads). On the basis of the number of contacts, synaptic arrangements associated with the labeled boutons could be subgrouped into simple (one or two contacts), intermediate (three or four contacts), and complex (five or more contacts) types. The labeled boutons varied from round to elongated forms with smooth to more irregular or scalloped contours. The boutons with scalloped contour were much more frequent in the complex type. The boutons of the intermediate type were significantly smaller than the complex type and larger than the simple type.

The SA periodontal afferent terminals participated in each type of synaptic arrangements in Vpv, but were mostly of the simple type in Vo. r. The size of labeled boutons was significantly larger in Vpv than in Vo. r. The total number of axodendritic and axoaxonic contacts per labeled bouton was significantly higher in Vpv than in Vo. r. Another difference was the more frequent occurrence of synaptic triads in Vpv than in Vo. r.

These observations provide evidence that sensory information from primary afferent fibers is processed in a different manner in the two subnuclei. © 1994 Wiley‐Liss, Inc.
Developmental changes in the laminar termination of a fibre cutaneous sensory afferents in the rat spinal cord dorsal horn
Authors: Fitzgerald M. , Butcher T. , Shortland P.
Published: January 2005

In order to establish the specificity of growth and termination of dorsal root afferents within the developing spinal cord, the central dorsal horn terminals of myelinated sensory afferents were labelled at various stages in the rat from embryonic day (E)18 through to postnatal day (P) 35 using horseradish peroxidase conjugated to choleragenoid (B‐HRP), The preferential labelling of A fibre afferents with this tracer was found to be as clear in the neonate as has been reported for the adult. The results show that while the somatotopic arrangement of A fibre afferent terminals in the dorsal horn is established early in development, the laminar projections are not. Following peripheral nerve or local skin injections of B‐HRP, A fibre terminals were found to project throughout laminae I to V, including laminae II (substantia gelatinosa). This widespread termination was observed consistently until the end of the third postnatal week. After P22 the terminal field becomes restricted to the normal laminae III to V. © 1994 Wiley‐Liss, Inc.
Dynamics of retinotectal synaptogenesis in normal and 3‐eyed frogs: Evidence for the postsynaptic regulation of synapse number
Authors: Norden Jeanette J. , Constantine‐Paton Martha
Published: January 2005

Quantitative stereological methods were used to determine if the number, density, and types of synaptic connections formed during development are regulated by presynaptic input or by postsynaptic target cells in the optic tectum of normal and 3‐eyed Rana pipiens tadpoles and frogs. Our analysis indicates that the number and size of synapses is approximately the same in both tecta of 3‐eyed tadpoles and frogs, even though one tectal lobe is receiving input from twice the normal complement of retinal ganglion cells. Moreover, the number and size of synapses in the tectal lobes of 3‐eyed animals did not differ significantly from values determined for normal tadpoles and frogs of the same developmental stage. These data suggest strongly that developing tectal cells regulate the number of synaptic contacts they will form. Differences in several morphological features between singly and doubly innervated tecta, however, including synapse density, distribution and complexity, amount of extracellular space, and number of myelin figures, suggest that the presence of supernumerary input retards tectal maturation. We propose that the noncorrelated activity of retinal ganglion cell terminals in the doubly innervated tectum results in fewer stabilized synapses per unit volume of neuropil and in the delayed maturation of the tectal neuropil. Taken together, our data suggest a complex dynamic interaction between retina and tectum during development. © 1994 Wiley‐Liss, Inc.
Parvalbumin immunoreactivity in the thalamus of guinea pig: Light and electron microscopic correlation with gamma‐aminobutyric acid immunoreactivity
Authors: de Biasi S. , Arcelli P. , Spreafico R.
Published: January 2005

The relationship of the calcium binding protein parvalbumin (PV) with gamma‐aminobutyric acidergic (GABAergic) neurons differs within different thalamic nuclei and animal species. In this study, the distribution of PV and GABA throughout the thalamus of the guinea pig was investigated at the light microscopic level by using immunoperoxidase methods. Intense PV labelling was found in all the GABAergic neurons of the reticular nucleus and in scattered GABAergic neurons in the anteroventral nucleus, whereas GABAergic interneurons in the ventrobasal and lateral geniculate nuclei were not PV labelled.

At the electron microscopic level, preembedding immunuperoxidase for PV was combined with postembedding immunogold for GABA. In the ventrobasal nucleus, four types of profiles were recognized: 1) terminals with flattened vesicles and forming symmetric synapses, which were labelled with both PV and GABA and could therefore be identified as afferents from the reticular nucleus; 2) boutons morphologically similar to presynaptic dendrites of interneurons, labelled only with GABA; 3) large terminals with round vesicles and asymmetric synapses, labelled only with PV, which contacted GABAergic presynaptic dendrites in glomerular arrangements and resembled ascending excitatory afferents; and 4) terminals unlabelled by either antiserum.

In the ventrobasal nucleus of the guinea pig a double immunocytochemical labelling permits therefore the differentiation of two populations of GABAergic vesicle‐containing profiles, i. e., the terminals originating from reticular nucleus (that are double labelled) and the presynaptic dendrites originating from interneurons (that are GABA‐labelled only). The possibility to differentiate GABAergic inputs from the reticular nucleus and from interneurons can shed light to the functional interpretation of synaptic circuits in thalamic sensory nuclei. © 1994 Wiley‐Liss, Inc.
Histological and ultrastructural localization of the kainate receptor subunits, KA2 and GluR6/7, in the rat nervous system using selective antipeptide antibodies
Authors: Petralia Ronald S. , Wang Ya‐Xian , Wenthold Robert J.
Published: January 2005

Kainate receptors are found throughout many regions of the brain and presumably contribute to responses of neurons to glutamate and other excitatory amino acids. Two affinity‐purified polyclonal antibodies that recognize the kainate binding subunits, KA2 and GluR6, were made using C‐terminus peptides. A previous study demonstrated that each antibody is specific for its subunit, although antibody to GluR6 recognizes GluR7 to some extent (hence the designation GluR6/7). Vibratome sections immunostained with either antibody showed light to moderate staining in many structures in the brain as well as in cervical spinal cord, dorsal root and vestibular ganglia, and pineal and pituitary glands. Moderate levels were seen in the olfactory bulb, cerebral cortex, caudate/putamen, and hypothalamus, whereas much of the thalamus was stained lightly. In the hippocampus, CA3 pyramidal cells were stained more densely than CA1 pyramidal cells—the difference more evident with antibody to GluR6/7. In addition, neuropilar staining was denset in the stratum lucidum of the CA3 region. In the brainstem, staining was moderate to moderately dense in a number of sensory, motor, and reticular nuclei. The moderately dense staining in the reticulothalamic nucleus and pontine nuclei with antibody to GluR6/7 may represent its recognition of GluR7. In the cerebellum, staining was moderate in granular and molecular layers with antibody to KA2 and in the molecular layer with antibody to GluR6/7, whereas it was moderately dense to dense in the granular layer with the GluR6/7 antibody. Outside of the brain, densest staining was seen localization of immunostaining was examined in the hippocampus, cerebral cortex, and cerebellar cortex. Typically, major staining was in postsynaptic densities apposed by unstained presynaptic terminals with round or mainly round vesicles and in associated dendrites. The light microscope pattern of staining was fairly similar to that of previous [3H]kainate binding and in situ hybridization studies. In addition, comparision with previous studies on distribution of other types of glutamate receptors indicates that KA2 and GluR6/7 are found with various other subunits in many of the same cell populations throughout the nervous system. © 1994 Wiley‐Liss, Inc.
Morphology of retinal axons induced to arborize in a novel target, the medial geniculate nucleus. I. Comparison with arbors in normal targets
Authors: Pallas S. L. , Hahm J. , Sur M.
Published: January 2005

Ferret retinal axons can be induced to innervate the medial geniculate nucleus (MGN) by a combination of brain lesions early in development. Our previous work suggests that the retinal ganglion cells responsible for this plasticity are W cells. The present study continues this work with a morphological investigation of normal retinal ganglion‐cell axons and retinal ganglioncell axons induced to arborize in the MGN. Retinal axons were bulk filled with horseradish peroxidase placed in the optic tract, and individual axons were serially reconstructed from sagittal sections. The control population consisted of fine‐caliber axons arborizing in the superior colliculus (SC) and in the ventral C laminae of the lateral geniculate nucleus (LGN) of normal ferrets. We also compared the axons in the MGN of lesioned ferrets to intracellularly filled X and Y axons from normal ferrets as reported by Roe et al. ([1989] J. Comp. Neurol. 288:208).

We have found that the retino‐MGN axons in the lesioned ferrets do not resemble X or Y axons in normal ferrts in axon diameter, arbor volume, bouton number, or bouton density. However, they do resemble the fine‐caliber, presumed W axons arborizing in the C laminae of the LGN and in the SC of normal ferrets. Thus, this study, in combination with previous studies, suggests strongly that W retinal ganglion cells are responsible for the retinal input to the MGN in lesioned animals. In addition, we find that the retino‐MGN axons are of two types, branched and unbranched, which may correspond to different subtypes of retinal W cells. © 1994 Wiley‐Liss, Inc.
Expression of multiple neuregulin transcripts in postnatal rat brains
Authors: Chen Maio S. , Bermingham‐McDonogh Olivia , Danehy Francis T. , Nolan Colleen , Scherer Steven S. , Lucas Joy , Gwynne David , Marchionni Mark A.
Published: January 2005

The distribution of neuregulin transcripts in rat brains was studied by both RNA blotting and in situ hybridization. Our data demonstrate that multiple neuregulin transcripts are expressed in neurons of the basal forebrain, the hippocampus, the diencephalon, the cerebellum, the brainstem, and the spinal cord. Developmental changes in the distribution of neuregulin transcripts were observed only in the cerebellum and the hippocampus. The intense neuregulin hybridization signals in the brainstem motor and sensory nuclei and the spinal motor neurons are suggestive of a functional involvement of neuregulins in motor and sensory systems. The expression of neuregulins in other parts of the brain also indicates that these factors are involved in a variety of central nervous system functions. © 1994 Wiley‐Liss, Inc.
Characterization of trout galanin and its distribution in trout brain and pituitary
Authors: Anglade Isabelle , Wang Yunxia , Jensen Jorgen , Tramu Gerard , Kah Olivier , Conlon J. Michael
Published: January 2005

Galanin was purified from an extract of the stomach of the rainbow trout, Oncorhynchus mykiss, and its primary structure was established as Gly‐Trp‐Thr‐Leu‐Asn‐Ser‐Ala‐Gly‐Tyr‐Leu10‐Leu‐Gly‐Pro‐His‐Gly‐Ile‐Asp‐Gly‐His‐Arg20‐Thr‐Leu‐Ser‐Asp‐Lys‐His‐Gly‐Leu‐Ala. Trout galanin shows six amino acid substitutions compared with pig galanin, but the N‐terminal region (residues 1–14) has been fully conserved. The distribution of galanin‐immunoreactive (GAL‐IR) structures in the trout brain and pituitary was studied via immunohistochemistry. GAL‐IR cell bodies were observed only in the caudal telencephalon, the preoptic region, and the mediobasal hypothalamus. GAL‐IR fibers, however, are widely distributed throughout the brain, with a much lower density in the midbrain and posterior brain than in the tel‐ and diencephalon. Particularly dense innervation of the mediobasal hypothalamus, the ventral and supracommissuralis parts of the caudal telencephalon, and the region above and below the anterior commissure was observed. A heavy innervation of the pituitary was consistently detected. GAL‐IR fibers were present in neurohypophyseal digitations of both the anterior and intermediate lobes with highest density in the region of the proximal pars distalis, where growth hormone and gonadotropic cells are located. Fibers were also seen in digitations of the rostral pars distalis, in particular between the prolactin follicles. The distribution of GAL‐IR neurons in the central nervous system and pituitary of the trout suggests that the peptide may exercise an important role in the regulation of neuroendocrine functions, particularly those related to reproduction. © 1994 Wiley‐Liss, Inc.
Mu, delta, and kappa opioid receptor mRNA expression in the rat CNS: An in situ hybridization study
Authors: Mansour Alfred , Fox Charles A. , Burke Sharon , Meng Fan , Thompson Robert C. , Akil Huda , Watson Stanley J.
Published: January 2005

The μ, δ, and κ opioid receptors are the three main types of opioid receptors round in the central nervous system (CNS) and periphery. These receptors and the peptides with which they interact are important in a number of physiological functions, including analgesia, respiration, and hormonal regulation. This study examines the expression of μ, δ, and κ receptor mRNAs in the rat brain and spinal cord using in situ hybridization techniques. Tissue sections were hybridized with 35S‐labeled cRNA probes to the rat μ (744–1, 064 b), δ (304–1,287 b), and κ (1,351–2,124 b) receptors. Each mRNA demonstrates a distinct anatomical distribution that corresponds well to known receptor binding distributions. Cells expressing μ receptor mRNA are localized in such regions as the olfactory bulb, caudate‐putamen, nucleus accumbens, lateral and medial septum, diagonal band of Broca, bed nucleus of the stria terminalis, most thalamic nuclei, hippocampus, amygdala, medial preoptic area, superior and inferior colliculi, central gray, dorsal and median raphe, raphe magnus, locus coeruleus, parabrachial nucleus, pontine and medullary reticular nuclei, nucleus ambiguus, nucleus of the solitary tract, nucleus gracilis and cuneatus, dorsal motor nucleus of vagus, spinal cord, and dorsal root ganglia. Cellular localization of δ receptor mRNA varied from μ or κ, with expression in such regions as the olfactory bulb, allo‐ and neocortex, caudate‐putamen, nucleus accumbens, olfactory tubercle, ventromedial hypothalamus, hippocampus, amygdala, red nucleus, pontine nuclei, reticulotegmental nucleus, motor and spinal trigeminal, linear nucleus of the medulla, lateral reticular nucleus, spinal cord, and dorsal root ganglia. Cells expressing, κ receptor mRNA demonstrate a third pattern of expression, with cells localized in regions such as the claustrum, endopiriform nucleus, nucleus accumbens, olfactory tubercle, medial preoptic area, bed nucleus of the stria terminalis, amygdala, most hypothalamic nuclei, median eminence, infundibulum, substantia nigra, ventral tegmental area, raphe nuclei, paratrigeminal and spinal trigeminal, nucleus of the solitary tract, spinal cord, and dorsal root ganglia. These findings are discussed in relation to the physiologica functions associated with the opioid receptors.