Nucleus Tractus Spinalis Nervi Trigemini Research Articles

Mapping of enkephalins and adrenocorticotropic hormone in the squirrel monkey brainstem.

An immunocytochemical technique has been used to study for the first time the distribution of fibers and cell bodies containing leucine-enkephalin (leu-enk), methionine-enkephalin (met-enk) or adrenocorticotropic hormone (ACTH) in the whole brainstem of the squirrel monkey Saimiri sciureus. Cell bodies containing leu-enk or met-enk were found in the superior colliculus and the formatio reticularis tegmenti mesencephali, respectively. No immunoreactive cell bodies containing ACTH were observed. Leu-enk-immunoreactive fibers were observed in 40 brainstem nuclei/tracts/regions, fibers containing met-enk were found in 38 brainstem nuclei/tracts/regions and fibers containing ACTH were found in 26 nuclei/tracts/regions. In the latter case, the density of immunoreactive fibers was always low. A high/moderate density of leu-enk- or met-enk-immunoreactive fibers were found in 18 and 16 brainstem nuclei/tracts/regions, respectively. The distribution of immunoreactive fibers containing leu-enk or met-enk was quite similar, with both leu-enk and met-enk observed in 82.5% of the squirrel monkey brainstem nuclei/tracts/regions. This relationship is less marked for met-enk and ACTH (60.5%) and even lower for leu-enk and ACTH (52.5%). In 42.5% of the nuclei/tracts/regions of the squirrel monkey brainstem (colliculus superior, substantia grisea centralis, nucleus interpeduncularis, nucleus tractus spinalis nervi trigemini, nucleus tractus solitarii, nucleus parabrachialis, formatio reticularis, substantia nigra), we observed fibers containing all three neuropeptides. The widespread distribution reported here suggests that enkephalins and ACTH can be involved in several physiological functions. The distribution of the immunoreactive fibers reported here is quite similar to that previously reported for enkephalins and ACTH in Macaca species and humans.

Distribution of Neurotensin and Somatostatin-28 (1-12) in the Minipig Brainstem.

Using an indirect immunoperoxidase technique, an in depth study has been carried out for the first time on the distribution of fibres and cell bodies containing neurotensin and somatostatin-28 (1-12) (SOM) in the minipig brainstem. The animals used were not treated with colchicine. The distribution of neurotensin- and SOM-immunoreactive fibres was seen to be quite similar and was moderate in the minipig brainstem: a close anatomical relationship between both neuropeptides was observed. The distribution of cell bodies containing neurotensin or SOM was quite different and restricted. Cell bodies containing neurotensin were found in four brainstem nuclei: nucleus centralis raphae, nucleus dorsalis raphae, in the pars centralis of the nucleus tractus spinalis nervi trigemini and in the nucleus ventralis raphae. Cell bodies containing SOM were found in six nuclei/regions of the brainstem: nucleus ambiguus, nucleus dorsalis motorius nervi vagus, formatio reticularis, nucleus parabrachialis medialis, nucleus reticularis lateralis and nucleus ventralis raphae. According to the observed anatomical distribution of the immunoreactive structures containing neurotensin or SOM, the peptides could be involved in sleep-waking, nociceptive, gustatory, motor, respiratory and autonomic mechanisms.

Distribution of CGRP in the minipig brainstem

For the first time, an in-depth study has been made of the distribution of fibers and cell bodies containing calcitonin gene-related peptide (CGRP) in the minipig brainstem using an indirect immunoperoxidase technique. The animals studied were not treated with colchicine. Cell bodies containing CGRP were found in 20 nuclei/regions of the brainstem. These perikarya were located in somatomotor, brachiomotor and raphae nuclei, nucleus ambiguus, substantia nigra, nucleus reticularis tegmenti pontis, nucleus prepositus hypoglossi, nuclei olivaris inferior and superior, nuclei pontis, formatio reticularis, nucleus dorsalis tegmenti of Gudden, and in the nucleus reticularis lateralis. Fourteen of the 20 brainstem nuclei showed a high density of immunoreactive cell bodies. In comparison with other species, the minipig, together with the rat, show the most widespread distribution of cell bodies containing CGRP in the mammalian brainstem. Immunoreactive fibers were also observed in the brainstem. However, in the minipig brainstem the density of these fibers is low, as in many brainstem nuclei only single immunoreactive fibers were observed. A high density of immunoreactive fibers was only observed in the pars caudalis of the nucleus tractus spinalis nervi trigemini and in the nucleus ventralis tegmenti of Gudden. According to the observed anatomical distribution of the immunoreactive structures containing CGRP, the peptide could be involved in motor, somatosensory, gustative, and autonomic mechanisms.

Neuron-Specific Mitochondrial DNA Deletion Levels in Sporadic Alzheimer´s Disease

Oxidative stress is implicated in the pathogenesis of neurodegenerative diseases, including sporadic Alzheimer´s disease (AD). Mitochondrial DNA (mtDNA) deletions are markers of oxidative damage and increase with age. To unravel the impact of mtDNA damage on AD development, we analyzed mtDNA deletion levels in diverse neuronal cell types of four brain regions (hippocampal CA1 and CA2 regions, nucleus tractus spinalis nervi trigemini, and the cerebellum) that exhibit differing levels of vulnerability to AD related changes at progressive Braak stages compared with age-matched controls. Neurons from these four brain regions were collected using laser microdissection, and analyzed using quantitative polymerase chain reaction (qPCR). Although, no correlation between mtDNA deletion levels and AD progression were found, the data revealed regional and cell type specific selective vulnerability towards mtDNA deletion levels. In conclusion, unexpected results were obtained as granule cells from the cerebellum and neurons from the nucleus tractus spinalis nervi trigemini of the brain stem displayed significant higher mtDNA deletion levels than pyramidal cells from hippocampal CA1 and CA2 region in age and AD.

Distribution of methionine-enkephalin in the minipig brainstem

We have studied the distribution of immunoreactive cell bodies and axons are containing methionine-enkephalin in the minipig brainstem. Immunoreactive axons were widely distributed, whereas the distribution of perikarya was less widespread. A high or moderate density of axons containing methionine-enkephalin were found from rostral to caudal levels in the substantia nigra, nucleus interpeduncularis, nucleus reticularis tegmenti pontis, nucleus dorsalis raphae, nucleus centralis raphae, nuclei dorsalis and ventralis tegmenti of Gudden, locus ceruleus, nucleus sensorius principalis nervi trigemini, nucleus cuneatus externalis, nucleus tractus solitarius, nuclei vestibularis inferior and medialis, nucleus ambiguus, nucleus olivaris inferior and in the nucleus tractus spinalis nervi trigemini. Immunoreactive perikarya were observed in the nuclei centralis and dorsalis raphae, nucleus motorius nervi trigemini, nucleus centralis superior, nucleus nervi facialis, nuclei parabrachialis medialis and lateralis, nucleus ventralis raphae, nucleus reticularis lateralis and in the formatio reticularis. We have also described the presence of perikarya containing methionine-enkephalin in the nuclei nervi abducens, ruber, nervi oculomotorius and nervi trochlearis. These results suggest that in the minipig the pentapeptide may be involved in many physiological functions (for example, proprioceptive and nociceptive information; motor, respiratory and cardiovascular mechanisms).

28. Multifocal symmetrical necrotising encephalopathy (MSNE) in Simmental crosses in Scotland

We have studied the distribution of immunoreactive cell bodies and axons are containing methionine-enkephalin in the minipig brainstem. Immunoreactive axons were widely distributed, whereas the distribution of perikarya was less widespread. A high or moderate density of axons containing methionine-enkephalin were found from rostral to caudal levels in the substantia nigra, nucleus interpeduncularis, nucleus reticularis tegmenti pontis, nucleus dorsalis raphae, nucleus centralis raphae, nuclei dorsalis and ventralis tegmenti of Gudden, locus ceruleus, nucleus sensorius principalis nervi trigemini, nucleus cuneatus externalis, nucleus tractus solitarius, nuclei vestibularis inferior and medialis, nucleus ambiguus, nucleus olivaris inferior and in the nucleus tractus spinalis nervi trigemini. Immunoreactive perikarya were observed in the nuclei centralis and dorsalis raphae, nucleus motorius nervi trigemini, nucleus centralis superior, nucleus nervi facialis, nuclei parabrachialis medialis and lateralis, nucleus ventralis raphae, nucleus reticularis lateralis and in the formatio reticularis. We have also described the presence of perikarya containing methionine-enkephalin in the nuclei nervi abducens, ruber, nervi oculomotorius and nervi trochlearis. These results suggest that in the minipig the pentapeptide may be involved in many physiological functions (for example, proprioceptive and nociceptive information; motor, respiratory and cardiovascular mechanisms).

Fine structure of the trigeminal nerve nucleus of the domestic fowl

The trigeminal nerve nuclei are examined light- and electron-microscopically in the adult domestic fowl. The nucleus sensibilis principalis nervi trigemini is formed by scarce, medium-sized, round-to-ovoid polygonal neurons. The Nissl bodies are concentrated around the nucleus and consist of short cisterns of the rough endoplasmic reticulum densely bordered with ribosomes. The nucleus tractus spinalis nervi trigemini extends to the first segments of the cervical cord. The rostral part of the nucleus is characterized by medium-sized polygonal neurons. Their cell bodies are densely packed with coarse Nissl bodies. Small multiforme cell types with large nuclei frequently showing two nucleoli predominate in the caudal part. The motorical main portion, nucleus motorius nervi trigemini consists of medium-sized as well as great polygonal neurons. The accessory portion, nucleus motorius dorsalis nervi trigemini, consists of medium-sized polygonal neurons. Both nuclei show the typical motoneuron cytomorphology. In the neuropil, the axodendritic synapses can be differentiated into five types. Occasionally, densely packed glial lamellae and giant mitochondria occur.

Age-related increase in cgrp binding site densities in rat cerebellum

The distribution of calcitonin (CT) binding sites in serial sections of the rat brain and spinal cord has been examined by an ‘in vitro’ autoradiographic technique using a radioisotope-sensitive sheet film and [125I]salmon CT. Autoradiograms of the diencephalic region had the highest grain density throughout the entire hypothalamus, with the exception of the nuclei ventromedialis, posterior and mammillaris, which were not labeled at all. In the brainstem, large amounts of grains were found in the ventrolateral division of the periaqueductal gray, in the locus coeruleus, in the nucleus tractus spinalis nervi trigemini and in the raphe obscurus, pallidus and magnus, while a widespread and lower grain density was observed in the reticular formation. In the spinal cord the labeling was discretely localized in laminae IV, V and VI of the dorsal horn. The observed distribution of CT binding sites is closely related to the neuroendocrine and analgesic effects of exogenous CT and reinforces the concept of a possible neuromodulatory role proposed for the peptide at brain level.

Anatomical distribution of somatostatin immunoreactivity in the infant brainstem

The distribution of somatostatin-immunoreactive structures in the infant brainstem was investigated using the peroxidase-antiperoxidase technique. A wide distribution of somatostatin-immunoreactive cell bodies and fibers was observed throughout the brainstem. Numerous somatostatin-immunoreactive cell bodies and fibers were present in several areas of the brainstem including the substantia grisea centralis and the reticular formation. Some immunoreactive cell bodies were seen in cranial nerve nuclei such as the nucleus praepositus, the nucleus nervi hypoglossi and the vestibular nuclei. Immunoreactive fibers were seen in the nucleus cuneatus, the locus coeruleus, the nucleus tractus solitarius, the nucleus ambiguus, the nucleus tractus spinalis nervi trigemini and the dorsal horn of the spinal cord. These data were in agreement with previous works on the human adult. However, a high density of somatostatin-immunoreactive cell bodies and fibers in the interpeduncular nucleus and in the nucleus centralis superior, and a dense network of somatostatin-immunoreactive fibers in the dorsal part of the nucleus inferior olivarius, were also observed. The role of somatostatin in some brainstem nuclei and its probable implication in some specific neuropathological diseases of the infant brainstem is discussed.

Afferent and efferent connections of brainstem locomotor regions: Study by means of horseradish peroxidase transport technique

Afferent and efferent connections of the hypothalamic and mesencephalic locomotor regions and also the bulbar locomotor strip were studied in cat using retrograde (horseradish peroxidase) transport technique. To study the sources of afferent projections, the enzyme microinjections were performed exactly into the same brain sites eliciting treadmill locomotion by means of electrical stimulation. When studying efferent projections horseradish peroxidase labeled neurons were revealed within locomotor regions after enzyme microinjections into different brain structures. Experimental data have shown that the hypothalamic and mesencephalic locomotor regions have mutual afferent and efferent projections with numerous brain areas including interconnections. Apart from the entopeduncular nucleus, the great number of different sensory nuclei are noted: among the sources of afferent projections are the nucleus tractus spinalis nervi trigemini, nucleus cuneatus, nucleus tractus solitarius and vestibular nuclei. In addition, after horseradish peroxidase injection into the mesencephalic locomotor region labeled neurons were found in the cochlear nuclei. Direct descending neuronal projections of the hypothalamic and mesencephalic locomotor regions are distributed mainly in the ipsilateral brainstem. Only a few of them reach the lumbar spinal cord. The most marked efferent projections of given regions are those to the brainstem reticular formation. After horseradish peroxidase injection into a functionally identified bulbar locomotor strip, labeled neurons were revealed in different stem regions mainly caudal to the enzyme injection site. The existence of a locomotor strip as an independent structural formation is called into question. When studying the locomotor region connections, the structural heterogeneity of these regions is revealed. Transitory fibers of ascending tracts are presumably within their limits side by side with neurons. The role of these fibers in stepping initiation by electrical stimulation of locomotor regions remains uncertain.

Distribution of substance P-like immunoreactive structures in the brainstem of the adult human brain: an immunocytochemical study

The distribution of substance P-like immunoreactive (SPI) structures in the brainstem of the adult human was investigated by the avidin-biotinylated peroxidase complex method for immunocytochemistry. SPI structures were widely distributed in the brainstem, and particularly dense in the substantia nigra, peripheral portions of the colliculus inferior, central gray matter, parabrachial area, nucleus dorsalis tegmenti of Gudden, nucleus reticularis tegmenti pontis, nucleus tractus solitarii, nucleus dorsalis motorius nervi vagi, and nucleus tractus spinalis nervi trigemini.

Eel calcitonin binding site distribution and antinociceptive activity in rats

The distribution of binding site for [ 125I]-eel-calcitonin (ECT) to rat central nervous system, studied by an autoradiographic technique, showed concentrations of binding in the diencephalon, the brain stem and the spinal cord. Large accumulations of grains were seen in the hypothalamus, the amygdala, in the fasciculus medialis prosencephali, in the fasciculus longitudinalis medialis, in the ventrolateral part of the periventricular gray matter, in the lemniscus medialis and in the raphe nuclei. The density of grains in the reticular formation and in the nucleus tractus spinalis nervi trigemini was more moderate. In the spinal cord, grains were scattered throughout the dorsal horns. Binding of the ligand was displaced equally by cold ECT and by salmon CT(sCT), indicating that both peptides bind to the same receptors. Human CT was much weaker than sCT in displacing [ 125I]-ECT binding. The administration of ECT into the brain ventricles of rats dose-dependently induced a significant and long-lasting enhancement of hot-plate latencies comparable with that obtained with sCT. The antinociceptive activity induced by ECT is compatible with the topographical distribution of binding sites for the peptide and is a further indication that fish CTs are active in the mammalian brain.

Distribution of GABA-T-intensive neurons in the rat hindbrain.

The pharmacohistochemical method previously used to identify the distribution in rat brain of gamma-aminobutyric acid transaminase (GABA-T)-intensive neurons has been applied to the rat pons and medulla. The method involves systemic administration of the irreversible GABA-T inhibitor Gabaculine and the detection, 12 to 15 hours after the injection of the newly synthesized GABA-T by histochemical means. GABA-T-intensive neurons were found to be rich in the following hindbrain structures: inferior colliculus, nuclei of the raphe system, nuclei parabrachialis dorsalis and ventralis, nucleus cuneiformis, nucleus vestibularis medialis, nucleus tractus spinalis nervi trigemini, nucleus vagus, nucleus cochlearis, nucleus reticularis lateralis, nucleus ambiguus, nucleus cuneatus lateralis, inferior olive, and reticular formation of the pons and medulla. Neurons of the deep cerebellar nuclei and the rostral portion of the lateral vestibular nucleus were negative for GABA-T but were surrounded by granular staining indicative of impinging GABA-T-rich nerve endings. These results provide further support for the hypothesis that GABA neurons are far more GABA-T-intensive than other neurons in the central nervous system.

Immunohistochemical distribution of somatostatin-like immunoreactivity in the central nervous system of the adult rat

The localization and distribution of somatostatin (growth hormone release-inhibiting hormone; somatotropin release-inhibiting factor) have been studied with the indirect immunofluorescence technique of Coons and collaborators and the immunoperoxidase method of Sternberger and coworkers using specific and well-characterized antibodies to somatostatin, providing semiquantitative, detailed maps of somatostatin-immunoreactive cell profiles and fibers. Our results demonstrate a widespread occurrence of somatostatin-positive nerve cell bodies and fibers throughout the central nervous system of adult, normal or colchicine-treated, albino rats. The somatostatin cell bodies varied in size from below 10μm up to 40 μm in diameter and could have only a few or multiple processes. Dense populations of cell somata were present in many major areas including neocortex, piriform cortex, hippocampus, amygdaloid complex, nucleus caudatus, nucleus accumbens, anterior periventricular hypothalamic area, ventromedial hypothalamic nucleus, nucleus arcuatus, medial to and within the lateral lemniscus, pontine reticular nuclei, nucleus cochlearis dorsalis and immediately dorsal to the nucleus tractus solitarii. Extensive networks of nerve fibers of varying densities were also found in most areas and nuclei of the central nervous system. Both varicose fibers as well as dot- or “dust-like” structures were seen. Areas with dense or very dense networks included nucleus accumbens, nucleus caudatus, nucleus amygdaloideus centralis, most parts of the hypothalamus, nucleus parabrachialis, nucleus tractus solitarii, nucleus ambiguus, nucleus tractus spinalis nervi trigemini and the dorsal horn of the spinal cord. One exception is the cerebellum which only contained few somatostatinpositive cell bodies and nerve fibers. It should be noted that somatostatin-positive cell bodies and fibers did not always conform to the boundaries of the classical neuroanatomical nuclei, but could often be found in areas between these well-established nuclei or occupying, in varying concentrations, only parts of such nuclei. It was difficult to identify with certainty somatostatin-immunoreactive axons in the animals studied. Some pathways could, however, be demonstrated, but further experimental studies are necessary to elucidate the exact projections of the somatostatin-immunoreactive neurons in the rat central nervous system.

Acetylcholinesterase changes in the central nervous system of mice during the development of morphine tolerance addiction and withdrawal

The distribution of acetylcholinesterase in the brain is studied during the development of morphine tolerance and through a period of withdrawal to elucidate the possible role of this enzyme in producing physical dependence in mice. Tolerance and physical dependence are produced in male albino mice by giving morphine sulphate subcutaneously at eight hourly intervals, in an increasing dose of 10 mg/kg body weight every 24 hours, for 15 days. The animals are considered addicted, when they received an otherwise lethal dose, 150 mg/kg three times a day. The enzyme shows a marked elevation in the overall distribution during the development of physical dependence. The habenular complex, nuclei anterioventralis and medialis thalami, nucleus caudatus putamen, amygdaloideus lateralis, septal nuclei, nucleus nervi hypoglossi, nucleus reticularis lateralis, tuberculum olfactorium, nucleus tractus diagonalis brocae, stratum pyramidale hippocampi, nucleus paraventricularis thalami, nucleus dorsalis nervi vagi, nucleus tractus spinalis nervi trigemini and nucleus reticularis thalami show an increase in the enzyme activity. This enhancement is not linear with the increase in dosage. Withdrawal is characterised by a sudden fall in the activity of acetylcholinesterase in the above mentioned areas of brain.

Mapping of CRF-immunoreactive nerve fibers in the medulla oblongata and spinal cord of the rat

By use of an antiserum raised against Corticotropin Releasing Factor (CRF 1–41), nerve fibers can be stained in the medulla oblongata and spinal cord of rats. A dense plexus of CRF-immunoreactive (CRF i) nerve fibers is present in the nucleus tractus spinalis nervi trigemini from which fiber bundles enter the tractus spinalis nervi trigemini. Large numbers of CRF i fibers are present in the substantia gelatinosa of the spinal cord, while the tractus solitarius, the nucleus tractus solitarius and the nucleus ambiguus contain a low number of CRF i fibers. In rats treated with colchicine, CRF i cell bodies are found in the hypothalamus and occasionally in the nucleus tractus solitarius and the nucleus olivaris inferior. Posterolateral deafferentation of the hypothalamus did not result in a disappearance of the CRF i fibers in the medulla oblongata and spinal cord 7 days after surgery. These results indicate that CRF i fibers present in the spinal cord and medulla oblongata are part of a novel peptidergic neuronal system, which is different from the hypothalamo-infundibular CRF system.

Localization of calcitonin binding sites in rat central nervous system: Evidence of its neuroactivity

The distribution of calcitonin (CT) binding sites in serial sections of the rat brain and spinal cord has been examined by an ‘in vitro’ autoradiographic technique using a radioisotope-sensitive sheet film and [ 125I]salmon CT. Autoradiograms of the diencephalic region had the highest grain density throughout the entire hypothalamus, with the exception of the nuclei ventromedialis, posterior and mammillaris, which were not labeled at all. In the brainstem, large amounts of grains were found in the ventrolateral division of the periaqueductal gray, in the locus coeruleus, in the nucleus tractus spinalis nervi trigemini and in the raphe obscurus, pallidus and magnus, while a widespread and lower grain density was observed in the reticular formation. In the spinal cord the labeling was discretely localized in laminae IV, V and VI of the dorsal horn. The observed distribution of CT binding sites is closely related to the neuroendocrine and analgesic effects of exogenous CT and reinforces the concept of a possible neuromodulatory role proposed for the peptide at brain level.

Ontogeny of substance P-containing neuron system of the rat: Immunohistochemical analysis—II. Lower brain stem

Ontogeny of the substance P neuron system in the lower brain stem of the rat was investigated by means of the indirect immunofluorescence technique. Substance P-positive structures (cells and fibers) first appeared in the primordium of the ventral part of the nucleus tractus spinalis nervi trigemini (nVs), in the reticular formation between nucleus reticularis lateralis and nVs, and in the reticular formation between nVs and nucleus originis nervi facialis, respectively, at gestational day 14. After that time, substance P-positive structures made their appearance gradually in various areas of the lower brain stem. The present study demonstrates that substance P-positive structures appear at a very early ontogenetical stage, which suggests that substance P may play a role in the development of the lower brain stem in addition to its role as a neurotransmitter or neuromodulator.

Experimental and morphological studies of the noradrenaline innervations in the nucleus tractus spinalis nervi trigemini of the rat with special reference to their fine structures

An attempt was made to elucidate the origins and fine structure of the noradrenaline (NA) terminals in the nucleus tractus spinalis nervi trigemini (Vsp) of the rat. The present study revealed that the NA in the Vsp is supplied from two NA neuron systems; bilateral locus coeruleus (LC) and medullary NA neuron group, on the grounds that: (1) two types of fluorescent fibers (fine and coarse) were identified in the Vsp; and (2) HRP injected into the Vsp resulted in labeling of neurons of the bilateral LC and bulbal NA areas, particularly the ipsilateral A 1 area. The fine structure of the NA terminals in the Vsp was investigated by a modified potassium permanganate fixation method. The NA terminals in this area contained a number of small cored vesicles together with a small number of large cored vesicles. The most frequent feature of the NA terminals found in this area was axo-dendritic contact. A lesser, but still substantial, number with axo-axonic contact were also noticed, in connection with which, it should be stressed that the non-NA terminals examined in this study were always presynaptic in structure, since the clear vesicles found in the non-NA terminals sometimes aggregated close to the contact membrane, where some of them fused or touched the membrane. As the dendrites showing a close relationship with the NA terminals were relatively large in size and contained a number of cytoplasmic organelles, these dendrites were assumed to be the proximal segments. At the contact zone, although no typical synaptic specialization was identified, the following profiles suggestive of synaptic-like contact were demonstrated: (1) somewhat dense material between contact membranes (intersynaptic filaments); (2) a slight accumulation of the dense materials adjacent to the postcontact membrane; (3) disarrangement of the contact membranes and enlargement of the space between these membranes; and (4) aggregation of the synaptic vesicles at the contact membrane with some of them fusing or touching the contact membrane.