bluuebunny/crossref_metadata_2025 huggingface dataset:
Target‐specific outgrowth from human mesencephalic tissue grafted to cortex or ventricle of immunosuppressed rats
Authors: Strömberg Ingrid , Bygdeman Marc , Almqvist Per
Published: January 2005

Human fetal mesencephalic tissue was grafted to rats with unilateral lesions of the nigrostriatal pathway. The animals were immunosuppressed with cyclosporine A. Grafts were placed either into the lateral ventricle ipsilateral to the lesion or in the cingulate cortex above corpus callosum. The grafts and newly formed fibers were visualized by immunohistochemistry with antibodies against tyrosine hydroxylase (TH) and the human Thy‐1 glycoprotein. TH‐positive fibers covered the total volume of striatum when the graft was placed either in the ventricle or in the cortex. When the transplant was located in the ventricle, TH‐positive cells migrated from the graft into host striatum. No cell migration was seen into any other areas than striatum. Cortex and septum were sparsely reinnervated by the graft, but not to a density higher than that normally seen. Globus pallidus was totally devoid of TH‐positive fibers. When the graft was placed in cingulate cortex, fiber bundles penetrated through corpus callosum into either striatum, to arborize in its dorsal parts, or followed the medial side of the lateral ventricle to ventral limbic areas, where a fiber network also was formed. Human specific Thy‐1‐immunohistochemistry revealed positivity only on the lesioned side. These data suggest that dopamine neurons in human mesencephalic tissue, grafted to the rat brain, can migrate specifically into host striatum. Furthermore, TH‐positive fiber outgrowth occurred only into dopamine denervated areas of the host, avoiding areas that are normally not innervated by nigral neurons, but also able to reach distant target cells.
Anatomy of dendrites in motoneurons supplying the intrinsic muscles of the foot sole in the aged cat: Evidence for dendritic growth and neo‐synaptogenesis
Authors: Ramírez V. , Ulfhake B.
Published: January 2005

Motoneurons (MNs) supplying the intrinsic muscles of the foot sole (IFS) were studied in the aged cat (> 15y). Axon conduction velocity of IFS MNs was 30–40% slower in the aged than in young adult cats. IFS MNs that appeared intact during intracellular recordings and labeling with horseradish peroxidase (HRP) were subjected to anatomical investigation of their dendrites. The results were compared with corresponding data from young adult (< 3y) cats.

The average number of dendrites per IFS MN was twelve in both the aged and young adults. However, the branching was significantly more extensive in the aged cat, thus indicating that proliferation of dendritic branches may occur during the later part of life. Topological analysis revealed a significant difference in the frequency distributions of nodal vertices between young adult and aged cats. In the young adult, the dendritic branching pattern was compatible with trees generated by outgrowth from terminal segments, while in the aged there was a clear indication of collateral outgrowth of branches.

The dendritic path distance and the length of terminal branches were similar in young adults and aged. The length of preterminal branches was shorter in the aged, while the combined dendritic length of a dendrite was larger compared to young adults. These data are consistent with the topological data, and add further evidence that the proliferation of branches in the aged cat may also take place from preterminal branches.

Light microscopic analysis revealed the presence of “growth cone‐like” extensions in the dendrites of the aged cats. Such profiles were not encountered in dendrites from young adults. Electron microscopic observations showed that these “growth cone‐like” formations were not artifacts and that they were apposed by numerous axonal boutons, of which a number made synaptic contact. A distinct feature of the extensions was their rich content of mitochondria and membranous elements. It was suggested that these “growth cone‐like” formations were sites at which novel synaptic connections are established, and that they may represent the initial stage of an outgrowth of new dendritic branches in the aged cat.

Local dendritic branch diameter related closely to the amount of dendritic membrane area located distally in both young adults and aged. Curve fitting disclosed that this relationship was quite similar for both age groups, despite concurrent differences in combined dendritic length and branching degree.
Distribution of zebrin II in the gigantocerebellum of the mormyrid fish Gnathonemus petersii compared with other teleosts
Authors: Meek J. , Hafmans T. G. M. , Maler L. , Hawkes R.
Published: January 2005

Immunocytochemistry has demonstrated unexpected heterogeneity among cerebellar Purkinje cells. For example, monoclonal antibody Mab anti‐zebrin II reveals parasagittal bands of immunoreactive Purkinje cells in the mammalian cerebellum, but reveals a non‐sagittal cerebellar compartmentation pattern in goldfish and gymnotiform fish. The present paper investigates the cerebellar compartmentation pattern, as reflected in the zebrin II distribution, in two other teleosts, the electric mormyrid fish Gnathonemus petersii with its large and regularly built gigantocerebellum, and the electrosensory osteoglossomorph teleost Xenomystis nigri, by‐using light as well as electron microscopic immunohistochemical techniques.

Zebrin II is expressed only in Purkinje cells, where it is present in the cytoplasm of all neuronal compartments, including spines, distal and proximal dendrites, the cell body, and the initial part, as well as terminal boutons of the axon. Other types of cerebellar neurons, including the eurydendroid projection neurons, are zebrin II‐negative. In Gnathonemus, zebrin II‐positive Purkinje cells are present in the large caudolateral part of the valvula, in lobes C2, C3, and C4 of the corpus, and in the anterior as well as the posterior part of the caudal cerebellar lobe. Zebrin II‐negative Purkinje cells are present in a continuous region encompassing the rostromedial part of the valvula, the lobus transitorius, lobe C1 and the ventral part of lobe C2, and in a small, lateral zone of the posterior part of the caudal lobe. In Xenomystis, all Purkinje cells, including those in the medial valvula and the posterior part of the caudal lobe, appear to react with mab anti‐zebrin II. This more widespread distribution may be due to the presence of a second antigenic polypeptide in this species.

On the basis of the present findings, it is concluded that the mormyrid lobus transitorius, lobe C1, and the ventral part of lobe C2 probably belong to the valvula, while the corpus is restricted to the dorsal part of lobe C2, lobe C3, and lobe C4. The functional significance of zebrin II expression for different subsets of teleostean Purkinje cells remains unclear, since comparisons of different teleosts reveal no general correlation with particular afferent or efferent connections, nor with special morphological features such as a dendritic palisade pattern or different arrangements of the Purkinje cell bodies. A comparison between mammals and teleosts suggests that a distinct parasagittal cerebellar zonation in teleosts is absent, and the major part of the teleostean cerebellum may be considered as a single (midsagittal) cerebellar zone, with about the same width as one mammalian parasagittal zone.
Small‐field neurons associated with oculomotor control in muscoid flies: Cellular organization in the lobula plate
Authors: Strausfeld Nicholas J. , Gilbert Cole
Published: January 2005

In muscoid flies, the lobula plate is the last station in the optic lobes for processing spectrally independent information from retinotopic afferents. Until recently, it was thought that most lobula plate neurons were color‐insensitive wide‐field tangential neurons that respond to direction‐specific motion. It has been suggested that certain of these supply inputs to premotor descending neurons involved in the control of flight and head movements. The present account describes a Golgi and cobalt‐silver analysis that reports evidence for additional lobula plate outputs, which are numerically complex and structurally elaborate. Beneath a retina with approximately 4,000 ommatidia, each of at least 15 populations of morphologically distinct small‐field neurons comprises approximately 110–440 elements that contribute to an isomorphic neural assembly subtending the whole retina. Morphologically small‐field efferents form three classes according to the origin of their axons and their arborization in the lobula plate and lobula. Neurons arising from the lobula plate, or shared by it and the lobula, visit dorsal descending neurons supplying the neck and flight motor in contrast to output neurons from the lobula, which project to ventral descending neurons supplying leg motor neuropils. The possible functional significance of small‐field lobula plate outputs onto descending neurons in the dorsal deutocerebrum is discussed.
Morphology of single medial vestibulospinal tract axons in the upper cervical spinal cord of the cat
Authors: Shinoda Yoshikazu , Ohgaki Tohru , Sugiuchi Yuriko , Futami Takahiro
Published: January 2005

The morphology of single medial Vestibulospinal tract (MVST) axons was investigated by iontophoretic injection of horseradish peroxidase into single axons at the upper cervical cord in pentobarbital‐anesthetized cats. MVST axons were identified by their monosynaptic responses to stimulation of the vestibular nerve and their direct responses to stimulation of the medial longitudinal fusciculus (MLF). Reconstructions of the axonal trajectory were made from 22 uncrossed and 19 crossed MVST axons at C1–C4. MVST axons ran in the ventral funiculus and gave rise to multiple axon collaterals to the upper cervical gray matter at different segments. These axons could be traced over the distance of 2.5–15.3 mm. Within these lengths, up to 9 axon collaterals were identified per axon (mean = s.d., 3.3 = 2.0, n = 41). Axon collaterals ramified in the gray matter several times and spread in a delta‐like manner in both the transverse and horizontal planes. There were usually gaps free from terminal arborizations between adjacent axon collaterals, since the rostrocaudal extension of individual axon collaterals (mean = 820 μm) was very much limited in contrast to wide intercollateral intervals (mean = 1,510 μm). Axon terminals were distributed mainly in laminae IX, VIII, and VII, and sometimes in laminae VI–IV. Most abundant terminals were observed in lamina IX, including the ventromedial (VM), the spinal accessory (SA) nuclei and the nucleus dorsomedial to the VM nucleus (DM nucleus). A majority of individual axon collaterals provided some terminal branches to at least one of the above three motor nuclei. Axon collaterals projecting to laminae VIII–VI without terminals in the motor nuclei were rarely observed. Individual MVST axons had a preferential terminal distribution in each motor nucleus, but all three motor nuclei were covered by axon terminals of an ensemble of all MVST axons, indicating that all neck muscles innervated by these three motor nuclei are influenced by vestibular inputs through MVST axons. Most collaterals from a single axon produced circumscribed terminal arborizations in one or two common areas in the transverse plane (mainly in lamina IX) that were in line with one another in the longitudinal axis of the cord. This longitudinal arrangement of discontinuous terminal arborizations in lamina IX from a single axon may correspond to a continuous sagittal column of motoneurons for a particular muscle. In addition, virtually all well‐stained MVST axons, both crossed and uncrossed, terminated in more than one motor nucleus of neck muscles in different combinations; single MVST axons were seen to project to the VM and SA nuclei, to the VM and DM nuclei, to the DM and SA nuclei, or to all three nuclei. Therefore, this result indicates that different sets of neck muscles innervated by a single MVST axon may constitute a functional synergy which participates in eliciting proper compensatory head movement.
Competition between an aphakic and an occluded eye for territory in striate cortex of developing rhesus monkeys: Cytochrome oxidase histochemistry in layer 4C
Authors: Tigges Margarete , Boothe Ronald G. , Tigges Johannes , Wilson James R.
Published: January 2005

Monkey models were used to examine the effects of competition for cortical territory between two eyes which were deprived simultaneously, but each eye experienced a different type of deprivation. We wanted to determine whether, under this condition of binocular unequal deprivation, the postnatal process of segregation into ocular dominance columns proceeds according to the same rules as those that apply to competition between a deprived and an undeprived fellow eye. Our models involved surgical removal of the natural lens from one eye in newborn rhesus monkeys. The resulting aphakia was corrected optically to a near point with extended‐wear contact lenses. The fellow eyes were either left unmanipulated or occluded with opaque contact lenses for varying periods during the day. At the end of the rearing period, some monkeys from each experimental group had either one eye enucleated or sustained injury to the retinal ganglion cells of one eye. The histochemical reaction for cytochrome oxidase was used to reveal the widths of ocular dominance columns in layer 4C of striate cortex in these monkeys. Under all experimental conditions, the axons related to the two eyes occupied segregated fields. The amount of cortical territory related to the aphakic, optically corrected eye depended on the manipulations of the fellow eye. In competition with an unmanipulated fellow eye, the aphakic eye's territory was greatly reduced. In competition with a part‐time occluded eye, its territory was reduced to a lesser degree, depending on the duration of the occlusion. In competition with a continuously occluded eye, however, the space related to the aphakic, optically corrected eye was slightly greater than that related to the occluded eye. Since neither the aphakic nor the continuously occluded eye receives normal visual input, they are both impaired. Therefore, they may compete on an almost equal basis for synaptic territory in layer 4C of striate cortex. Moreover, it is likely that activities originating in the aphakic and the continuously occluded eye are asynchronous, and that this condition is sufficient to drive the postnatal segregation of inputs from the two deprived eyes.
Dorsal root ganglion neurons projecting to the dorsal column nuclei of rats
Authors: Giuffrida R. , Rustioni A.
Published: January 2005

Dorsal root ganglion (DRG) neurons may give origin to ascending branches that terminate in the dorsal column nuclei (DCN); uncertainties still exist with regard to the proportion of these neurons in different DRGs and to the type of these neurons. The percentage and size of neurons that project to the DCN were determined in a large number of DRGs by means of the retrograde transport of colloidal gold‐labeled wheat germ agglutinin conjugated to enzymatically inactive horseradish peroxidase (WGAapoHRP‐AU). A total of 16,239 neurons was tallied in 80 DRGs from nine rats; 3,240 (20%) of these were retrogradely labeled by the tracer injected in the DCN. Percentages of DCN projecting neurons vary considerably at different segmental levels: they are higher in cervical (up to 63%) than in thoracic (up to 31% for T1, up to 12% for thoracic DRGs below T1) or lumbar DRGs (up to 15%). At cervical levels highest percentages were encountered in C6, C7, and C8 and lowest percentages in C2‐C4. At lumbar levels highest percentages were encountered in L4 and lowest in L1 and L6. When considering the soma size of DRG neurons it appears that: (1) there are more large cells, labeled and unlabeled, at cervical (38%) than at lumbar levels (30%) and more at lumbar than at thoracic levels (23%); (2) at every level, most labeled, i.e., projecting, neurons are large; and (3) DRGs with the highest proportions of large vs. small cells contain the highest percentages of DCN projecting neurons.

These results represent the first attempt at establishing the percentages and soma size of DCN projecting neurons from a large number of DRGs and at comparing the contribution to these nuclei from cervical, thoracic, and lumbar DRGs. Some of the differences in the ratio of projecting neurons at different levels may be explained on the basis of well‐known anatomical features, e.g., the projections to the Clarke's column of many DRG neurons in lumbar ganglia. The contribution of virtually exclusively large DRG neurons to the DCN, suggested by indirect or incomplete evidence, is demonstrated by the present retrograde labeling and soma size measurements. The results relate to the functional component of peripheral receptors that relay their input via the dorsal columns and do not seem to support a recent suggestion that a sizeable fraction of unmyelinated primary afferents ascend in the dorsal columns to terminate in the DCN.
Neuropeptide Y (NPY) and C‐flanking peptide of NPY in the pineal gland of normal and ganglionectomized sheep
Authors: Cozzi Bruno , Mikkelsen Jens D. , Ravault Jean‐Paul , Møller Morten
Published: January 2005

The present immunohistochemical study describes the presence and distribution of nerve fibers containing neuropeptide Y (NPY), and C‐Flanking Peptide Of NPY (CPON) in the pineal gland of the sheep. Nerve fibers were detected by using a series of antisera directed against NPY or against CPON. Many positive immunoreactive nerve fibers were identified in the pial capsule of the pineal, in connective septae and in the parenchyma between pinealocytes. The intraparenchymal fibers were particularly evident and created an extensive network throughout the gland. Nerve fibers immunoreactive for all the peptides were also observed in the posterior commissure and in the stria medullaris thalami. No NPY‐ or CPON‐positive neurons were found in the pineal gland.

In order to study the site of origin of NPY‐ and CPON‐immunoreactive nerve fibers, the superior cervical ganglia were bilaterally removed in a series of animals. Sympathetic denervation was checked by using an antiserum against tyrosine hydroxylase (TH). Nearly all TH‐immunoreactive elements disappeared in the pineal glands of animals sacrificed 15 days after surgery. Also the density of NPY‐ and CPON‐immunoreactive nerve fibers decreased in the animals after the ganglionectomy. However, a number of nerve fibers still remained in the gland. These data indicate that some NPY‐ and CPON‐immunoreactive nerve fibers of the sheep pineal gland derive from an extrasympathetic origin. The very dense innervation of the sheep pineal gland with nerve fibers containing NPY and CPON strongly indicates a functional role for this family of peptides in the pineal gland of this species.
Localization of FMRF amide‐like peptides in Caenorhabditis elegans
Authors: Schinkmann K. , Li C.
Published: January 2005

The neuropeptide FMRFamide (Phe‐Met‐Arg‐Phe‐NH2) is a member of a large family of related peptides that have been found throughout the animal kingdom. By using an antiserum specific for the Arg‐Phe‐NH2 moiety, we have found that about 10% of the neurons in the nematode Caenorhabditis elegans are immunoreactive. Most of these neurons, which include sensory, motor, and interneurons, were identified on the basis of their number, position, and projection pattern and by analysis of characterized mutants. Neurons that were immunoreactive in hermaphrodite animals were generally also found in males, but each sex had, in addition, sex‐specific immunoreactive cells. Staining of hermaphrodite animals from different larval stages suggests that the onset of FMRFamide‐like expression is differentially regulated among the cells. We have found a possible neuromodulatory role for the related peptide FLRFamide (Phe‐Leu‐Arg‐Phe‐NH2). In an egg‐laying assay, FLRFamide by itself was not active but could potentiate a serotonin effect. The FMRFamide‐like immunoreactivity was also used as a marker to examine the differentiation of cells that normally undergo programmed cell death. Cells that are destined to die in the Pn.a lineages appear to differentiate and adopt the fate of lineally equivalent cells before cell death.
Mapping of angiotensin II receptor subtype heterogeneity in rat brain
Authors: Song Keifu , Allen Andrew M. , Paxinos George , Mendelsohn Frederick A. O.
Published: January 2005

Angiotensin II (Ang II) exerts a number of central actions on fluid and electrolyte homeostasis, autonomic activity, and neuroendocrine regulation. In order to evaluate likely sites where these actions are mediated, Ang II receptor binding was localized in rat brain by in vitro autoradiography with the aid of the antagonist analogue l25I‐[Sar1, Ile8]Ang II. Two subtypes of Ang II receptor have been identified using recently developed peptide and nonpeptide antagonists. In the periphery, the receptor subtypes differ in distribution, second messenger coupling, and function. Brain Ang II receptor subtypes were therefore differentiated into AT‐1 (type I) and AT‐2 (type II) subtypes by using unlabelled nonpeptide antagonists specific for the two Ang II subtypes.

AT‐1 binding was determined to be that inhibited by Dup 753 (10 μM) and AT‐2 binding to be that inhibited by PD 123177 (10 μM). The reducing agent dithiothreitol (DTT) decreased binding to AT‐1 receptors and enhanced binding to AT‐2 receptors.

Many brain structures, such as the vascular organ of the lamina terminalis, subfornical organ, median preoptic nucleus, area postrema, nucleus of the solitary tract, and dorsal motor nucleus of the vagus, which are known to be related to the central actions of Ang II, contain exclusively AT‐1 Ang II receptors.

By contrast, the locus coeruleus, ventral and dorsal parts of lateral septum, superior colliculus and subthalamic nucleus, many nuclei of the thalamus, and nuclei of the inferior olive contain predominantly AT‐2 Ang II receptors.

The detailed binding characteristics of each subtype were determined by competition studies with a series of analogues of angiotensin and antagonists. The pharmacological specificity obtained in rat superior colliculus and the nucleus of the solitary tract agreed well with published data on AT‐1 and AT‐2 receptors, respectively.

There was a high degree of correlation between the distribution of Ang II binding sites with published data on Ang II‐immunoreactive fields and on the sites of Ang II‐responsive neurons.

The present study also reveals pharmacological heterogeneity of brain Ang II receptors. The subtype‐specific receptor mapping described here is relevant to understanding the role of angiotensin peptides in the central nervous system and newly discovered central actions of nonpeptide Ang II receptor antagonists.
Organization of parabrachial nucleus efferents to the thalamus and amygdala in the golden hamster
Authors: Halsell Christopher B.
Published: January 2005

While gustation in the hamster has been extensively studied at the behavioral and physiological level, very little is known about the central anatomy of the taste system. The purpose of this study was to trace the connections of the parabrachial nucleus (PBN) in the golden Syrian hamster (Mesocricetus auratus) using wheat germ agglutinin‐conjugated horseradish peroxidase. The PBN is the site of the second central synapse for the ascending gustatory system and receives taste afferents from the nucleus of the solitary tract. Following large injections into the PBN, anterogradely transported label was seen in the lateral hypothalamus dorsal thalamus, bed nucleus of the stria terminalis, and amygdala. The anatomy of the two primary targets, the ventral posteromedial thalamus and central nucleus of the amygdala, is described based on Nissl‐stained material, and acetylcholinesterase and NADH dehydrogenase histochemistry. Injections into these two regions revealed different patterns of efferents within the PBN. Following injections into the thalamus, retrogradely labelled cell bodies were distributed throughout the PBN subdivisions bilaterally, but concentrated in the central medial (CM) and external lateral (EL) subdivisions. Following injections into the amygdala, retrogradely labelled cell bodies were primarily in the ipsilateral PBN EL, while anterogradely transported label was distributed throughout much of the ipsilateral PBN. The majority of CM efferents projecting to the thalamus were elongate cells, whereas the majority of CM efferents to the amygdala were round‐oval cells. These results indicate that the ascending central gustatory system changes from a serial pathway (nucleus of the solitary tract‐PBN) to a parallel organization consisting of two major projections, the parabrachio‐thalamo‐cortical and parabrachio‐amygdaloid pathways.
Migration of astrocytes transplanted to the midbrain of neonatal rats
Authors: Zhou Hai Feng , Lund Raymond D.
Published: January 2005

Previous studies have indicated that transplanted astrocytes are able to survive, express glial fibrillary acidic protein (GFAP), and migrate in the host brain, and that the pattern and speed of astrocyte migration is largely determined by the location of the graft. We examine here the pattern of astrocyte migration in the midbrain by transplanting CD‐1 mouse corpus callosum (P2–3) into the midbrain of neonatal rats. The location of the grafts and the distribution of donor astrocytes were assessed by using a monoclonal antibody (anti‐M2) specific for mouse astrocytes. A characteristic donor astrocyte distribution was seen. The highest density of cells was in the region of the substantia nigra (SN); lower numbers were found in the medial geniculate nucleus (MGN). Donor astrocytes were also found in the superior colliculus (SC) and central gray region, but only when the body of a graft was located nearby. [3H]thymidine studies showed that the concentrations of donor astrocytes in the SN were not the result of high levels of mitotic activity: all indications were that the proportion of dividing donor cells closely matched that of host glia. The pattern of astrocyte migration in the midbrain did not follow the course established by radial glia and was not influenced by axonal degeneration in the SC after removal of eyes. Moreover, donor cells failed to migrate along the course of axonal outgrowth from co‐grafted retinae. Reciprocally, axonal elongation from retinal grafts did not follow the pathway of astrocyte migration, thus suggesting that astrocyte migration and neuronal outgrowth follow different cues.
Differential development of the dual serotoninergic fiber system in the cerebral cortex of the cat
Authors: Vu Dzung H. , Törk Istvan
Published: January 2005

The changes in distribution and density of the serotoninergic innervation of the cerebral cortex were studied in kittens from birth (PO) to 60 days of age (P59). Three cortical areas were sampled: prefrontal, primary auditory, and primary visual areas. Two systems of serotoninergic axons were demonstrated by immunocytochemical techniques: the fine axon system characterized by small fusiform varicosities up to 1 μm in diameter, and the beaded axon system, the fibers of which have round varicosities up to 5 μm in diameter. The density of the two types of fibers across the cortical layers at different ages was measured with a semiautomatic computerized system. In all three areas, the density of fine axons increased steadily from birth, although the pattern of innervation changed from an even distribution at PO to a distinct concentration of the fibers in layers I–III by week 2 in the prefrontal cortex and by week 3 in auditory and visual cortices. By contrast, the beaded axons first appeared in the cortex at week 2 for the prefrontal cortex, at week 3 in auditory and visual areas. Initially, these fibers were distributed throughout all cortical layers and were of much lower density than the fine axons. At later ages the beaded axons became confined to layers I–III where they gradually increased in number, and from week 4, they formed pericellular arrays which were only observed in the prefrontal and auditory cortices, not in visual cortex.

These findings provide further evidence for the existence of two parallel subsystems of serotoninergic axons which are different not only in their morphology and nuclear origin, but also in their development. Our finding that the two serotoninergic fiber systems arrive in the cortex in two different stages suggests that they have differential roles in development. The late formation of the pericellular arrays indicates that the formation of the specific connections made by the beaded fibers could be dependent on a certain degree of maturity of the target neurons.
Neonatal enucleation induces correlated modification in sensory responsive areas and pial angioarchitecture of the parietal and occipital cortex of albino rats
Authors: Wolff Joachim R. , Toldi József , Siklós László , Fehér Ottó , Joó Ferenc
Published: January 2005

This study was carried out to investigate whether correlations existing in normal adult rats (Ambach et al., '86) between functional characteristics of neocortical areas and their pial angioarchitechture can be correspondingly modified under pathological conditions. The right eyes of albino rats were enucleated on the 1st, 8th, 15th and 30th day after birth, respectively. At the age of 3 to 4 months, the responsiveness of the parieto‐occipital cortex to sensory stimuli was studied in enucleated animals and age matched controls. After the mapping of visually and somatosensorily evoked potentials, the vascular system was filled with dye. Monocular enucleation at birth induced bilateral modifications in sensory responsiveness and corresponding changes in pial angioarchitecture, especially in the venous drainage fields. In comparison with the controls, a considerable expansion was observed in the overlapping zone between visually and somatosensorily responsive areas. In contrast, borders of the visual cortex toward the auditory and retrosplenial areas were essentially stable. Corresponding changes were found in the pial distribution patterns of cerebral veins but not of arteries. The major effect of neonatal enucleation on angioarchitecture was a change in the subdivision of the parietooccipital veins drainage fields. This was due to a significant enlargement of the anterior accessory occipital (O3) vein, which compressed the drainage fields of the parietal and occipital veins and completely separated them from one another. The results suggest that during ontogenesis: (1) alterations in the formation of sensory input may interfere with neocortical angiogenesis, especially the structuring of veins, (2) after monocular enucleation this influence is prominent in parietal and occipital cerebral veins, and (3) these angiogenetic processes are vulnerable only during the perinatal and early postnatal period.
Secondary vestibular cholinergic projection to the cerebellum of rabbit and rat as revealed by choline acetyltransferase immunohistochemistry, retrograde and orthograde tracers
Authors: Barmack N. H. , Baughman R. W. , Eckenstein F. P. , Shojaku H.
Published: January 2005

Previously we have shown that four regions of the cerebellum, the uvula‐nodulus, flocculus, ventral paraflocculus, and anterior lobe 1, receive extensive, but not exclusive, cholinergic mossy fiber projections. In the present experiment we have studied the origin of three of these projections in the rat and rabbit (uvula‐nodulus, flocculus, ventral paraflocculus), using choline acetyltransferase (ChAT) immunohistochemistry in combination with a double label, retrogradely transported horseradish peroxidase (HRP).

We have demonstrated that in both the rat and rabbit the caudal medial vestibular nucleus (MVN) and to a lesser extent the nucleus prepositus hypoglossus (NPH) contain ChAT‐positive neurons. Neurons of the caudal MVN are double‐labeled following HRP injections into the uvula‐nodulus. HRP injections into the uvula‐nodulus also labeled less than 5% of the neurons in the cholinergic vestibular efferent complex.

Fewer ChAT‐positive neurons in the MVN and some ChAT‐positive neurons in the NPH are double‐labeled following HRP injections into the flocculus. Almost no ChAT‐positive neurons in the MVN and some ChAT‐positive neurons in the NPH are double‐labeled following HRP injections into the ventral paraflocculus.

Injections of Phaseolus leucoagglutinin (PHA‐L) into the caudal MVN of both the rat and rabbit demonstrated projection patterns to the uvula‐nodulus and flocculus that were qualitatively similar to those observed using ChAT immunohistochemistry.

We conclude that the cholinergic mossy fiber pathway to the cerebellum in general and the uvula‐nodulus in particular is likely to mediate secondary vestibular information related to postural adjustments.
Galanin‐like innervation of rat submandibular and sublingual salivary glands: Origin and effect on acinar cell membranes
Authors: Konopka L. M. , May V. , Forehand C. J.
Published: January 2005

The distribution and source of a galanin‐like innervation of rat salivary glands has been examined. Additionally, submandibular and sublingual acinar cell membrane responses to galanin or a cholinergic agonist were studied. Galanin‐immunoreactive fibers were observed throughout the submandibular and sublingual glands in association with ducts and acini. A subset of submandibular ganglion cells expresses galanin immunoreactivity. Parasympathectomy resulted in a marked decrease in galanin immunoreactivity in the glands. Sympathectomy resulted in marked reduction of dopamine β‐hydroxylase immunoreactivity with no appreciable change in galanin immunoreactivity. Retrograde labeling experiments demonstrated that galanin‐immunoreactive sensory neurons in the trigeminal ganglion do not innervate the submandibular or sublingual gland. These results indicate that the galanin‐like innervation of rat salivary glands is derived from parasympathetic nerves to the glands.

Since rat sublingual glands contain largely mucous acini while rat submandibular gland acini are seromucous, electrophysiological responses to galanin and the muscarinic agonist, bethanechol, were compared. Agonist‐induced voltage shifts varied between the two glands. The galanin‐induced response at the level of the resting membrane potential in submandibular acinar cells was a hyperpolarization, while that in sublingual acinar cells was a depolarization. There was also a greater voltage dependence to the galanin‐induced submandibular response than to the sublingual response. Differences were also noted in the acinar cell response to cholinergic stimulation between these glands.

These results demonstrate the existence of a galanin‐like innervation to salivary glands that may be functionally relevant. Moreover, the results challenge the idea that agonist‐induced membrane responses are similar among acinar cells of different glands.
Anatomical organization of the hypophysiotrophic systems in the electric fish, Apteronotus leptorhynchus
Authors: Johnston Sheila A. , Maler L.
Published: January 2005

The organization of afferents to the pituitary was investigated by applying DiI crystals to the pituitary or pituitary stalk of the gymnotiform electric fish, Apteronotus leptorhynchus. Most hypophysiotrophic cells were found in the hypothalamus and were distributed throughout its rostrocaudal extent: nucleus preopticus periventricularis, pars anterior and posterior; suprachiasmatic nucleus; anterior, dorsal, ventral, lateral, and caudal hypothalamic nuclei; and nucleus tuberis lateralis, pars anterior and posterior. In addition a small number of retrogradely labeled cells were found in the ventral telencephalon (area ventralis, pars ventralis) and, most surprisingly, in a thalamic nucleus (nucleus centralis posterioris). The nucleus preopticus periventricularis pars posterior and the anterior hypothalamic nucleus appear to correspond to the parvicellular and magnocellular divisions of the nucleus preopticus of other teleosts. Integration of these results with immunohistochemical localization of monoamines and neuropeptides in the apteronotid brain suggests many homologies between the hypophysiotrophic nuclei of teleosts and other vertebrates, including mammals.

Apteronotus communicates electrically during agonistic and sexual interactions. There are numerous anatomical links between the hypophysiotrophic systems and the brain areas related to electrocommunication.
Organization of the superior olivary complex in the guinea pig: II. Patterns of projection from the periolivary nuclei to the inferior colliculus
Authors: Schofield Brett R. , Cant Nell B.
Published: January 2005

The superior olivary complex is a major source of auditory projections to the inferior colliculus. Although the projections from the medial and lateral superior olivary nuclei have been well characterized, projections from the surrounding periolivary nuclei have received relatively little attention. In the guinea pig, cytoarchitectonic criteria can be used to distinguish 11 periolivary nuclei that can be divided into four groups. These are: (1) a lateral group that comprises the anterolateral and posteroventral periolivary nuclei and the lateral nucleus of the trapezoid body; (2) a dorsal group that comprises the dorsal and dorsolateral periolivary nuclei; (3) a ventral group that comprises the rostral, ventromedial, and anteroventral periolivary nuclei and the ventral nucleus of the trapezoid body; and (4) a medial group that comprises the superior paraolivary nucleus and the medial nucleus of the trapezoid body.

In the present study we used horseradish peroxidase and fluorescent tracers to identify olivocollicular cells in each of the periolivary nuclei. The lateral, dorsal, and medial periolivary groups project bilaterally, and the ventral periolivary group projects ipsilaterally. Within groups, individual nuclei contain different numbers of olivocollicular cells. The posteroventral periolivary nucleus is the only periolivary nucleus that does not project to the inferior colliculus. The superior paraolivary nucleus is the only periolivary nucleus that contains significant numbers of individual cells that project to both inferior colliculi. The remaining periolivary nuclei project only ipsilaterally or contain separate populations of cells that project to the two inferior colliculi.
Serotoninergic, noradrenergic, and peptidergic innervation of Onuf's nucleus of normal and transected spinal cords of baboons (papio papio)
Authors: Rajaofetra N. , Passagia J.‐G. , Marlier L. , Poulat P. , Pellas F. , Sandillon F. , Verschuere B. , Gouy D. , Geffard M. , Privat A.
Published: January 2005

We have investigated with light and electron microscope immunocytochemistry the aminergic and peptidergic innervation of Onuf's nucleus in adult baboons. This nucleus, located in the ventrolateral part of the sacral spinal cord (S2 and S3), is considered to control urethral and anal sphincters and penile muscles. By comparison of intact and transected spinal cords, we have found that serotoninergic innervation has two origins: first, supraspinal, innervating the whole nucleus, with a possible predominance in the dorsal half; and second, intraspinal, corresponding to the ventral half of the nucleus. Thyrotropin‐releasing hormone innervation appears largely coincident with serotonin, both in intact and transected spinal cords. Noradrenaline is exclusively of supraspinal origin, as attested by its disappearance below the level of the section. Substance P, calcitonin genex‐related peptide, and Leux‐ and Metx‐enkephalin, which profusely innervate Onuf's nucleus, are on the contrary not affected by the transection. They most likely originate from the cord itself or the dorsal root ganglia. Thus, Onuf's nucleus innervation in the baboon arises both from supraspinal and intraspinal sources.

The present study provides an anatomical basis for both voluntary and reflex controls of excretory and sexual functions in a primate. The same neurotransmitter (serotonin) according to its cell origin and discrete topography could exert different influences upon the same effector system.
Distribution of vasopressin and oxytocin cells and fibres in the hypothalamus of the domestic pig (Sus scrofa)
Authors: Van Eerdenburg Frank J. C. M. , Swaab Dick F. , Van Leeuwen Fred W.
Published: January 2005

The distribution of vasopressin and oxytocin cells and fibres was studied in the pig hypothalamus by means of monoclonal antibodies, in order to prevent the non‐specific staining that is characteristic for the pig. The nucleus circularis is described for the first time in the pig hypothalamus and consists of both oxytocin and vasopressin containing cell bodies. A cell group, characteristic for the pig and horse, lateral and caudal from the vascular organ of the lamina terminals, was found to be continuous with the supraoptic nucleus. It contained only oxytocin and it is proposed that this group be called pars dorsomedialis of the supraoptic nucleus. In this study, vasopressin has been demonstrated for the first time in the suprachiasmatic nucleus of the pig. The discussion focusses on how our findings in the pig differ from vasopressin and oxytocin systems identified in other mammalian species.
A light and electron microscopic study of intracellularly HRP‐labeled lumbar motoneurons after intramedullary axotomy in the adult cat
Authors: Lindå H. , Cullheim S. , Risling M.
Published: January 2005

In contrast to many other neurons in the central nervous system, spinal motoneurons in adult cats have been shown to regenerate their axons after an axotomy accomplished within the CNS compartment. This regenerative capacity may be the result of extrinsic influences, or intrinsic properties of the motoneurons themselves, or interactions between extrinsic and intrinsic factors. As part of the effort to establish circumstances of importance for this central regeneration, a detailed analysis of the morphology of lumbar motoneurons was performed 3–11 weeks following a ventral funiculus axotomy. Fourteen large neurons considered to be intramedullarly axotomized alpha motoneurons were labeled intracellularly with horseradish peroxidase.

Twelve out of the fourteen analyzed neurons had an axonlike regenerating process. These twelve neurons could, in turn, be separated into two groups, based on the proximity of the axonal lesion and the proximal morphology of the regenerating process. Thus, after a comparatively proximal axotomy, new axons were produced, originating either from the cell soma or from a distal dendritic branch. After a more distal axotomy, but still intramedullarly, it seemed as if the proximal part of the original axon always persisted and subsequently regenerated.

Analysis of the relation between the cell soma diameter and the diameter and number of its stem dendrites revealed that dendrites become thinner and also decrease in number after an intramedullary axotomy. In this way, it may be calculated that the total dendritic surface area of lesioned motoneurons will decrease by approximately half. In four neurons, most dendrites had an abnormal appearance in the light microscope with increasing diameter of distal branches. Ultrastructural analysis revealed that such dendrites were surrounded by myelin sheaths.

Small filopodia in close relation to axon terminals were found to emerge from the cell membrane of the lesioned motoneurons. Their function may be to establish contact with presynaptic elements and then retract them to the cell membrane.

We interpret the morphological changes of the motoneurons as signs of a large capacity for axonal regeneration, even after axotomy in the central nervous system.
Independent mosaics of large inner‐ and outer‐stratified ganglion cells in the goldfish retina
Authors: Cook Jeremy E. , Becker David L. , Kapila Rakesh
Published: January 2005

Goldfish retinal ganglion cells were filled with horseradish peroxidase and studied in flatmounts. Two regular mosaics of large neurons with many of the properties of mammalian alpha ganglion cells were found, differing from each other in spacing, size, and dendritic stratification. The existence of biplexiform ganglion cells with additional dendrites in the outer plexiform layer was also confirmed.

One of the two alpha‐like mosaics consisted of giant ganglion cells with thick primary dendrites and large, sparsely branched dendritic trees in the outer sublamina of the inner plexiform layer (IPL). In fish 55–65 mm long, about 300 formed a tessellated array across each retina. Their somata (mean area 277 ± 6 μm2) were displaced to varying degrees into the IPL, neighbours in the mosaic often occupying different levels. Their dendrites ramified in one stratum near the inner nuclear layer, at a mean depth of 70.8 ± 0.5% of the IPL.

The other alpha‐like mosaic comprised about 900 large ganglion cells, with slightly smaller somata (mean area 193 ± 4 μm2) in the ganglion cell layer. Most of their dendrites lay in a narrow stratum at 41.9 ± 0.5% of the depth of the IPL. However, deviations (usually into more vitread strata) were common, which was not true for similar cells in the distantly related cichlid fish Oreochromis. Measurements of nearest neighbour distance (NND) for 4 outer and 4 inner mosaics showed that they were at least as regular as the alpha cell mosaics of mammals: the ratio of the mean NND to the standard deviation ranged from 4.03 for the least regular outer mosaic to 6.47 for the most regular inner mosaic.

The wide phylogenetic distribution of these paired, regular mosaics points to a fundamental role in vision. The presence of some variability in dendritic stratification even within the exceptionally regular inner‐stratified mosaic suggests that classifications based entirely on the detailed morphology of individual neurons may not always correlate well with their primary functional roles. Where possible, neuronal morphology and spatial distribution should be studied together.
Rapid growth of astrocytic processes in N. Magnocellularis following cochlea removal
Authors: Rubel Edwin W. , MacDonald Glen H.
Published: January 2005

Removal of the cochlea or pharmacological blockade of eighth nerve activity in young postnatal chickens results in rapid transneuronal cell death and atrophy in neurons of n. magnocellularis. The present experiments were designed to examine the influence of afferent input on astrocyte structure in n. magnocellularis. Young chickens were subjected to unilateral cochlea removal. At times ranging from 5 minuses to 72 hours later, the brainstems were histologically processed with a polyclonal antibody against glial fibrillary acidic protein (GFAP). A second group of chick brainstems was impregnated by a Golgi method 6 hours after unilateral cochlea removal and impregnated three‐dimensional reconstructions were made of glial cells in n. magnocellularis (NM).

Analyses of GFAP positive processes in NM revealed an observable increase in the number of astrocytic processes at the borders of the nucleus within 30 minutes of cochlea removal and a twofold increase in GFAP + glial processes by 6 hours. A secondary increase in the number and density of GFAP + processes occurred between 24 and 72 hours following cochlea removal, during the period of axonal degeneration, and transneuronal cell atrophy and death.

Analyses of astrocytes impregnated by the Golgi method revealed that individual glial cells had increased their total process length and the number of processes by approximately twofold by 6 hours after cochlea removal.

These results suggest that the structure of astrocytes is rapidly and dramatically influenced by the level of excitatory activity in a neuronal system. Furthermore, the similarity of results obtained with GFAP immunohistochemistry and three‐dimensional reconstruction of astrocytes provides evidence that the short‐term changes observed following cochlea removal represent the actual growth of glial processes. We speculate that modulations in glial processes as a function of afferent activity may act to influence synaptic efficacy.