Nerve terminals in human periodontal ligament as demonstrated by immunohistochemistry for neurofilament protein (NFP) and S-100 protein.

Nerve terminals in the human periodontal ligament were investigated by immunohistochemistry for neurofilament protein (NFP) and glia-specific S-100 protein. The human periodontal ligament was found to be innervated by NFP-immunoreactive nerve fibers, and contained free and specialized nerve endings; essentially all these nerve fibers were associated with S-100 protein-immunoreactive elements. Free nerve endings showing tree-like ramifications were frequently observed along the whole length of the tooth. The specialized nerve endings consisting of thick nervous elements were classified into four types as follows: Ruffini-like endings which were composed of expanded nerve terminals arranged in a dendritic fashion were found mainly around the root apex; coiled nerve endings were located in the mid-region of the periodontal ligament; spindle-shaped types, and expanded nerve endings, both rarely found near the root apex. Immunostaining for S-100 protein showed that no lamellated nerve terminals were found in the human periodontal ligament. The region-specific distribution of various nerve terminals demonstrated in this study seems to be suited to effectively receive mechanical stimuli to the teeth from various directions.

[Cholinergic innervation of vasopressin-containing cells of the blood vessels of the brain in man]. / Kholinergicheskaia innervatsiia vazopressinsoderzhashchikh kletok krovenosnykh sosudov golovnogo mozga cheloveka.

By means of immunochemical method the presence of vasopressin in the melanocytes of the man's brain arteries was found. The terminals of the cholinergic axons come to an end on the surface of these cells. It is suggested that the melanocytes take part in the regulation of the brain arteries mobility.

[Ultrastructural features of somatostatin-containing neurons of the hypothalamus of rats with protein insufficiency]. / Ul'trastrukturnye kharakteristiki somatostatinsoderzhashchikh neironov gipotalamusa krys pri belkovoi nedostatochnosti.

The electron microscopic investigation was performed to analyze somatostatin-contained nerve terminals in the median eminence of 21 days old malnourished rats' hypothalamus. In nerve terminals of malnourished animals in compared with controls ones there was found the increased density of granular vesicles (11.62 +/- 0.40 and 8.56 +/- 0.39 in 1 micron2, respectively) and decreased density of electron lucent vesicles with 120-160 nm diameter (1.66 +/- 0.18 and 3.43 +/- 0.26 in 1 micro2, respectively). The revealed increase in density of granular vesicles in axon terminals with positive immunohistochemical reaction to somatostatin in malnourished rats was explained by slow somatostatin release.

Ultrastructure of primary afferent fibres and terminals expressing alpha-galactose extended oligosaccharides in the spinal cord and brainstem of the rat.

The ultrastructural characteristics of primary afferent fibres, which express alpha-galactose extended oligosaccharides recognized by LD2 and LA4 monoclonal antibodies, and the subcellular localization of these oligosaccharides were studied. LD2 and LA4 antibodies both label intensely the plasma membrane of primary afferent fibres, and with LD2 antibody all immunoreactive profiles also possessed strong intracellular staining. In contrast, intracellular staining with LA4 antibody was observed in only a subpopulation of stained profiles. LD2-immunoreactive fibres were detected in trigeminal and Lissauer tracts and in lamina I (LI) and lamina II (LII), and appeared as a mixture of unmyelinated and myelinated fibres. The highest density of LD2-immunoreactive synaptic boutons was found in lamina II outer (LIIo). Many of the terminals were simple dome-shaped terminals, making single asymmetric synapses over small and medium-sized dendritic shafts and dendritic spines. All LA4-immunoreactive fibres were unmyelinated. In addition, some small scalloped central-glomerular terminals contacting two or three dendrites were found. LA4-immunoreactive fibres were found more frequently than terminals and appeared most heavily immunostained in trigeminal and Lissauer tracts. In the neuropil of LI and LII, LA4 profiles were generally very weakly immunostained, although a small sample of immunostained synaptic boutons was detected. All LA4-immunoreactive terminals were found in lamina II inner (LIIi) and made simple asymmetric axodendritic synapses. In addition to axons and terminals, some dendrites exhibited LD2 immunoreactivity and this was most intense in the region of synaptic vesicles. In addition to neurons, some endothelial cells were immunostained with LD2 antibody and astrocytes were immunostained with LA4 antibody.

Serotonin-containing axon terminals in the hypoglossal nucleus of the rat. An immuno-electronmicroscopic study.

The morphology and distribution of serotonin-containing axon terminals in the rat hypoglossal nucleus (XII) was investigated immunocytochemically at the electron microscopic level. Serotonin-positive profiles were found throughout all regions of XII and included unmyelinated axons, varicosities and axon terminals. Most labeled profiles (68.1%) were nonsynaptic unmyelinated axons and varicosities, while synaptic profiles, ending on dendrites and somata, were seen less frequently (28.7%). The majority of labeled axon terminals (76.9%) ended on small-to-medium-sized dendrites. Most axodendritic terminals contained small, round agranular vesicles (20-55 microns), several large (60-100 microns) dense core vesicles, and were associated with a pronounced asymmetric postsynaptic specialization. By contrast, labeled axosomatic terminals were seen less often than those ending on dendrites (23.0%). Axosomatic terminals typically contained small, round, agranular and large dense core vesicles and were associated with a symmetric or no postsynaptic specialization. These results provide the structural substrates for elucidating the functional role of serotonin in tongue control.

[Immunohistochemical localization of nerve terminals in the human gingiva. Use of a new neuronal marker]. / Localizzazione immunoistochimica dei terminali nervosi nella gengiva umana. Utilizzo di un nuovo marker neuronale.

The usefulness of classical techniques for sensory nerve ending detection is compromised by intrinsic limitations. The development of immunohistochemical methods has recently produced new information on the innervation pattern in different human tissues. This study presents the results obtained by use of a new antiserum, raised against a new marker of central and peripheral neurons (PGP 9.5), which selectively labels nerve fibers and neuroendocrine (APUD) cells also in human gingiva. The possible application of this method for further researches is also briefly discussed.

Distribution of peptidergic terminals of enteric origin in the rat celiac ganglion.

We examined the distribution of enterofugal nerve terminals of bombesin-, cholecystokinin- and vasoactive intestinal polypeptide-like immunoreactivity in the rat celiac-superior mesenteric ganglion complex. The majority of these nerve terminals were concentrated in the mesenteric side of the ganglion. The present findings suggest that some functional specialization occurs in the celiac ganglion of the rat.

Are there bulbospinal catecholaminergic neurones in the guinea pig equivalent to the C1 cell group in the rat and rabbit?

The C1 cell group in the rat is characterized by neurones which contain both adrenaline and phenylethanolamine-N-methyltransferase, and usually also neuropeptide Y (NPY). The former two substances are lacking in Guinea pig brainstem and spinal cord. We have examined the distribution of NPY- and tyrosine hydroxylase-immunoreactivity in the ventrolateral medulla and thoracolumbar intermediate zone of Guinea pig, as well as the distribution of catecholamine-containing neurone somata and spinal terminals visualized after formaldehyde-glutaraldehyde fixation. The results are compared with comparable immunohistochemical data obtained from rats and rabbits. Catecholaminergic neurones in the Guinea pig with locations and terminations that correspond to those of the C1 cell group in rat and its analogue in the rabbit appear to consist of two subgroups, with only the more caudal group containing NPY. The more rostral group requires pretreatment with monoamine oxidase inhibitor to permit visualization of catecholamine fluorescence, a property previously though to be characteristic of adrenergic neurones. This observation raises the possibility that the catecholaminergic cell group in the C1 region of rabbits may not contain adrenaline either.

Identification of noradrenergic nerve terminals immunoreactive for neuropeptide Y and vasoactive intestinal peptide in the rat kidney.

Cryostat- and vibratome-cut sections of rat kidneys were singly or doubly labeled to visualize immunoreactive tyrosine hydroxylase (THI), dopamine beta-hydroxylase (DBHI), vasoactive intestinal peptide (VIPI), and neuropeptide Y (NPYI). Rats were perfusion fixed with 2-4% paraformaldehyde with or without 0.15% picric acid and rinsed in buffer for 18-48 hr. Single antigens were labeled with horseradish peroxidase in vibratome sections, whereas cryostat sections were used to label one antigen with peroxidase and another with a fluorophore in the same tissue section. A dense plexus of DBHI noradrenergic nerves innervates the renal arterial tree, and such nerves innervate the interlobar veins and renal calyx as well. Immunoreactive NPY is colocalized in most of these nerves, but some intrarenal noradrenergic nerves do not contain NPY but do contain VIP immunoreactivity. The distribution of NPYI nerves resembles that of DBHI nerves, whereas most perivascular noradrenergic nerves immunoreactive for VIP innervate selected arcuate and interlobular arteries. A small population of nonadrenergic, VIPI nerves innervates the renal calyx.

Peptidergic innervation of the temporomandibular disk in the rat.

The peptidergic innervation of the temporomandibular disk was investigated in the postnatal young rat by using an indirect immunofluorescence method. Calcitonin gene-related peptide-containing nerve fibers were located around the blood vessels and terminated as free nerve endings in the disk. These nerve fibers may be of a sensory nature.

Carbohydrates of the vestibular end organs detected by lectins.

The presence of carbohydrates was investigated in the vestibular end organs of the guinea pig using FITC-lectins. The following sugars have been identified: N-acetyl-glucosamine, galactose, mannose and fucose. In contrast, N-acetyl-galactosamine was not clearly detected. These sugars were suggested to be closely related to the formation and maintenance of otoconia as well as of the cupula. N-acetyl-glucosamine was considered to be the major component of the glycocalyx and also suggested to have a function as an anchoring structure between the epithelial cell and the otolithic membrane or the cupula.

Distribution of terminals of thalamocortical fibers originating from the ventrolateral nucleus of the cat thalamus.

Anterograde labelling following focal injections of Phaseolus vulgaris leucoagglutinin was used to identify the threedimensional cortical distribution of thalamocortical (TC) fibers from the ventrolateral nucleus of the thalamus of the cat. The labelled TC fibers were distributed usually in layers I and III of the motor cortex and the terminals in layer III tended to aggregate into patches about 1-1.5 mm wide in a mediolateral direction. These patches were arranged in longitudinal strips about 2-5 mm long in a rostrocaudal direction and were separated by gaps of terminal free area.

Immunocytochemical analysis of calcitonin gene-related peptide and vasoactive intestinal polypeptide in Merkel cells and cutaneous free nerve endings of cats.

Calcitonin gene-related peptide (CGRP)- and vasoactive intestinal polypeptide (VIP)-immunoreactivity were observed to coexist in Merkel cells of cats. No differences in peptide content were found between Merkel cells located in epithelia of the hard palate, in hairy and glabrous skin of the upper lip, and in vibrissae follicles. CGRP- and VIP-immunoreactive nerve fibres were also found near CGRP/VIP-immunoreactive Merkel cells. In the vibrissae follicles some CGRP- and VIP-immunoreactive nerve terminals end abutting on the glassy membrane. Other CGRP-immunoreactive nerve fibres penetrate the epithelium of the skin and end within it. Electron microscopy of vibrissae follicles revealed that Merkel cell neurites are not immunostained and that immunostained nerve fibres form unmyelinated bundles before ending freely. Thus, CGRP- and VIP-immunoreactive nerve fibres in cat skin do not end as Merkel cell neurites but as different kinds of free nerve endings.

A topographic study of the course of nigral axons and of the distribution of pallidal axonal endings in the centre médian-parafascicular complex of macaques.

The combination of autoradiographic and topographic methods in macaques reveals that nigral axons only cross through the medial part of the parafascicular nucleus and end more dorsally and anteriorly in the thalamus. Pallidal endings are scarce in the centre médian and essentially located in the lateral parafascicular nucleus. It is proposed here to consider the centre médian-parafascicular complex as a part of the basal ganglia.

Neurons in the medial cortex give rise to Timm-positive boutons in the cerebral cortex of lizards.

The origin of Timm-positive presynaptic boutons in the cerebral cortex of the lizard, Podarcis hispanica, was investigated by injections of horseradish peroxidase (HRP)-saponine in Timm-positive areas, i.e. the dorsal and dorsomedial cortices. A broad retrograde labelling of cell somata in the medial cortex was found. Injections of HRP-saponine in the medial cortex resulted in broad anterograde labelling of boutons located in the Timm-positive zones. A double-labelling of the HRP labelled boutons was obtained by using the Neo-Timm or the sulphide-osmium methods. The present results suggest that neurons of the medial cortex send axons that terminate in Timm-positive boutons in the cerebral cortex of lizards.

Organization of calcitonin gene-related peptide-immunoreactive terminals in the primate dorsal horn.

The present paper is concerned with the arrangement of axons and synaptic terminals immunostained for calcitonin gene-related peptide (CGRP), a primary afferent marker, in the primate (Macaca fascicularis) dorsal horn. The CGRP axons and terminals are uniformly distributed in laminae I and II outer (o) but they are concentrated laterally and distributed intermittently in the reticulated region of lamina V. A prominent bundle of labeled axons is seen in the sacral cord dorsal to the central canal. Emphasis is given to the relation of CGRP-immunoreactive terminals to other terminals, both labeled and unlabeled, in laminae I and IIo. In this regard, adjacent CGRP-immunoreactive terminals are often united by puncta adhaerentia. Of particular interest is the observation that CGRP-immunoreactive terminals can be found presynaptic to other terminals which sometimes resemble central primary afferent endings. In addition CGRP-immunoreactive terminals end on other CGRP terminals. Both findings suggest that primary afferent terminals interact synaptically with other primary afferent terminals.

Membrane heterogeneity in sensory receptors of rat vibrissae: Merkel receptors differ from other nerve endings.

The cupric/ferrocyanide reaction was used to analyse cation-binding sites in rat vibrissae. The heminode of the last myelinated segment had moderate staining. No staining of any complex receptor was found except for Merkel receptors. Both the Merkel cell and associated nerve ending were stained except for their apposed cell membranes, suggesting either reciprocal membrane specialization at that site, or prevention of cupric/ferrocyanide penetration into the space between the two cells.

Regional heterogeneity in the distal motor axon: three zones with distinctive intrinsic components.

In this study we examined the distribution of cytoskeletal and other intrinsic axonal elements in motor nerve terminals in vivo. Components of axons were visualized with immunocytochemical staining of frozen longitudinal sections of muscle. Using these methods we compared the distribution of neurofilaments, tubulin, MAP2, actin and synaptic elements in distal regions of axons at and near neuromuscular junctions in rat muscles. Our results show that three discrete regions can be defined based on the anatomy and intrinsic components of distal axons. The preterminal axon, extending from its exit from the intramuscular nerve toward the neuromuscular junction, has a cytoskeletal composition similar to the more proximal axon with abundant staining of neurofilaments, tubulin, MAP2 and actin. The terminal arborization, a branched region of the axon extending through the endplate region, contains neurofilaments but little tubulin, actin, MAP2 or synaptic elements. Finally, the synaptic zone, demonstrated with antibodies to the synaptic vesicle protein synaptophysin, contains few cytoskeletal elements. We conclude that there is considerable regional heterogeneity in the composition of distal motor axons. The distribution of neurofilaments, other cytoskeletal elements and synaptic vesicle proteins varies among different discrete zones of terminal motor axons.

The co-localisation of substance P and VIP in cholinergic-type terminals of the rat parotid gland.

Parotid glands from the rat were examined for substance P (SP) and vasoactive intestinal polypeptide (VIP)-like immunoreactivity with the peroxidase-antiperoxidase (PAP) and immunogold methods. The majority of nerve terminals associated with the acinar secretory cells contained numerous small agranular vesicles measuring 40-60 nm in diameter and a few larger vesicles which had an electron-dense core and measured 90-120 nm in diameter. Electron-dense peroxidase reaction product indicative of SP and/or VIP-like immunoreactivity was found within the larger dense-cored vesicles and attached to the outer membrane of the small agranular vesicles. Some nerve terminals associated with the acinar cells contained no reaction product irrespective of whether sections were incubated for SP or VIP. With the immunogold method gold particles indicative of SP and/or VIP-like immunoreactivity were found associated with the larger dense-cored vesicles with very little gold labelling over the small agranular vesicles. When ultrathin sections were incubated for both SP and VIP-like immunoreactivity all of the labelled terminals examined contained gold particles indicative of the presence of both peptides. In several terminals individual dense-cored vesicles contained gold particles of different sizes which indicates co-existence of SP and VIP within the same vesicle. Several nerve terminals associated with the acinar cells contained no gold labelling of their synaptic vesicles. Occasionally nerve terminals were found around blood vessels that were positive for SP-like immunoreactivity and VIP-like immunoreactivity but none was found, using the immunogold method, that contained both peptides. Very few nerve terminals were found associated with ducts and none contained reaction product or gold particles indicative of SP or VIP-like immunoreactivity. The ultrastructural features of the nerve terminals containing SP and/or VIP-like immunoreactivity could not be distinguished from those that have been described as representing cholinergic terminals. The fact that the postganglionic parasympathetic secretomotor neurons contain, in addition to acetylcholine, two neuropeptides and the possible functional implications thereof are discussed.

Heterogeneous distribution of GABA-immunoreactive nerve fibers and axon terminals in the superior cervical ganglion of adult rat.

The distribution of axons and axon varicosities containing GABA was studied in the superior cervical ganglion of rat by light and electron microscopic immunohistochemistry. Two different polyclonal antibodies were used, which had been made against GABA conjugated by glutardialdehyde to bovine serum albumin. GABA-like immunoreactivity occurred in many axons within the cervical sympathetic trunk and in axons and axon varicosities around the principal nerve cells in the superior cervical ganglion. GABA-positive axons were intermingled with non-stained axons, except for a small group of fibers in the trunk where the staining was absent. The rostral part of the ganglion and some scattered patches were more densely innervated by GABA-positive axons than the middle and caudal parts. Within dense areas, some of the large ganglion cells were abundantly surrounded by GABA-positive nerve fibers, while the vicinity of others was devoid of any immunoreactive axon terminals. None of the principal ganglion cells contained GABA-like immunoreactivity, although a class of small cells scattered within the ganglion was stained. Transection of the cervical sympathetic trunk for 11 days caused the disappearance of GABA-like positivity from most of the fibers, and only very little GABA-like staining was revealed in some small cells, which resembled satellite cells. Ultrastructurally, the GABA-positive nerve fibers were unmyelinated. However, their terminal branches and varicosities accumulated around the perikarya and dendrites of certain principal ganglion cells were partly wrapped in glial processes. The present results provide evidence that the superior cervical ganglion of adult rat receives a significant number of GABA-positive axons from the cervical sympathetic trunk and that these axons provide an innervation which is heterogeneously distributed within the superior cervical ganglion and on ganglionic cells. The source and function of the GABA-positive axons remain to be elucidated.