Spinal Trigeminal Nucleus Caudalis Research Articles

Autoradiographic distribution of 125I-galanin binding sites in the rat central nervous system

Galanin (GAL) binding sites in coronal sections of the rat brain were demonstrated using autoradiographic methods. Scatchard analysis of 125I-GAL binding to slide-mounted tissue sections revealed saturable binding to a single class of receptors with a Kd of approximately 0.2 nM. 125I-GAL binding sites were demonstrated throughout the rat central nervous system. Dense binding was observed in the following areas: prefrontal cortex, the anterior nuclei of the olfactory bulb, several nuclei of the amygdaloid complex, the dorsal septal area, dorsal bed nucleus of the stria terminalis, the ventral pallidum, the internal medullary laminae of the thalamus, medial pretectal nucleus, nucleus of the medial optic tract, borderline area of the caudal spinal trigeminal nucleus adjacent to the spinal trigeminal tract, the substantia gelatinosa and the superficial layers of the dorsal spinal cord. Moderate binding was observed in the piriform, periamygdaloid, entorhinal, insular cortex and the subiculum, the nucleus accumbens, medial forebrain bundle, anterior hypothalamic, ventromedial, dorsal premamillary, lateral and periventricular thalamic nuclei, the subzona incerta, Forel's field H 1 and H 2, periventricular gray matter, medial and superficial gray strata of the superior colliculus, dorsal parts of the central gray, peripeduncular area, the interpeduncular nucleus, substantia nigra zona compacta, ventral tegmental area, the dorsal and ventral parabrachial and parvocellular reticular nuclei. The preponderance of GAL-binding in somatosensory as well as in limbic areas suggests a possible involvement of GAL in a variety of brain functions.

Histochemical demonstration of vibrissae-representing patchy patterns of cytochrome oxidase activity within the trigeminal sensory nuclei in the cat

Cytochrome oxidase histochemistry revealed patchy patterns of the enzyme activity in transverse sections through the caudal part of the ventral subnucleus of the principal sensory trigeminal nucleus, interpolar spinal trigeminal nucleus, and layer IV of the caudal spinal trigeminal nucleus in the cat. By the transganglionic transport method of horseradish peroxidase, the patterns were indicated to replicate the spatial array of the facial vibrissae.

Distribution of galaninlike immunoreactivity in the rat central nervous system

The localization of galanin (GAL) immunoreactive (IR) neuronal structures in the rat central nervous system has been investigated by using the indirect immunofluorescence technique. GAL-IR structures were seen in high concentrations in the hypothalamus, medulla oblongata, and spinal cord. Less extensive systems were detected in the telencephalon, thalamus, mesencephalon, and pons, while virtually no GAL-positive structures were seen in the olfactory bulb and cerebellum. Major populations of cell bodies staining for GAL-like material were seen in many areas. In the telencephalon somata were revealed in the bed nucleus of stria terminalis, in the nucleus of the diagonal band, medial septum, and in the medial aspects of the central amygdaloid nucleus, and in small numbers in cortical areas. The anterodorsal and periventricular nuclei of the thalamus contained positive cell bodies. In the hypothalamus GAL-IR somata were seen in the medial and lateral preoptic nuclei, arcuate nucleus, periventricular nucleus, in the dorsomedial nucleus, in the medial forebrain bundle area, in the tubular, caudal, accessory, supraoptic, and paraventricular magnocellular nuclei and lateral to the mammillary recess. The dorsal raphe nucleus hosted a large number of GAL-positive somata. Locus coeruleus of the pons contained a large number of GAL-IR perikarya. In the medulla oblongata positive somata were found in the caudal spinal trigeminal nucleus, the nucleus of the solitary tract, and in the ventral lateral area just rostral to area postrema. Small cell bodies were detected in the superficial layers of the dorsal horn of the spinal cord at all levels and in lamina X at lumbar levels. Analysis of GAL-positive fibers in the telencephalon revealed highly or medium-dense networks in the lateral septal nucleus, in the bed nucleus of stria terminalis, and in the central and medial amygdaloid nuclei. Positive fibers were found in the thalamus in and around the periventricular nucleus as well as in the lateral habenular nucleus and extending in a lateral, caudal direction from the third ventricle and fasciculus retroflexus to the lateral tip of the medial lemniscus. In the hypothalamus the external layer of the median eminence contained a very dense fiber network. Dense or medium-dense GAL-IR networks were detected in the periventricular nucleus, throughout the medial and lateral preoptic areas, in the medial forebrain bundle area, in the dorsomedial nucleus, and lateral to the mammillary recess. In the pons GAL-IR fibers were seen in the parabrachial nuclei, dorsal to the superior olive, and in the periaqueductal central gray.(ABSTRACT TRUNCATED AT 400 WORDS)

Anatomical evidence that the pontine lateral tegmental field projects to lamina I of the caudal spinal trigeminal nucleus and spinal cord and to the Edinger-Westphal nucleus in the cat

Autoradiographical tracing results in the cat indicate that the lateral pontine tegmental field projects mainly contralaterally to the marginal layer of the spinal trigeminal nucleus, to laminae I and II and the lateral part of laminae V and VI of the spinal cord and the Edinger-Westphal nucleus. It is pointed out that the projections from the lateral pontine tegmentum are very similar to the ones derived from the Edinger-Westphal nucleus and that these two areas are reciprocally connected. It is postulated that both areas may play a role in supraspinal pain control.

Immunoreactive glutamic acid decarboxylase in the trigeminal nucleus caudalis of the cat: a light- and electron-microscopic analysis.

This study used antisera directed against glutamic acid decarboxylase (GAD), the biosynthetic enzyme for gamma-aminobutyric acid (GABA), to examine the light- and electron-microscopic distribution of presumed GABA-ergic synapses in the medullary homologue of the cat spinal dorsal horn, the trigeminal nucleus caudalis. At the light-microscopic level, immunoreactive terminals were concentrated in the superficial dorsal horn, laminae I and II. Colchicine was generally ineffective in revealing the distribution of cell bodies. However, in two successful cases, the majority of labeled cells were found in the magnocellular layer, ventral to the substantia gelatinosa, a region that had a lower density of immunoreactive terminals. Other labeled neurons were scattered in laminae I and II. A variety of synaptic arrangements were found at the electron-microscopic level. These derived from two types of labeled terminals. One contained both small round vesicles and large dense-cored vesicles. The second contained small round and pleomorphic vesicles. Some immunoreactive GAD terminals contained a few flat vesicles. Labeled terminals predominantly formed axodendritic synapses, via symmetrical contacts. Several axoaxonic arrangements were also observed. In most cases, the GAD terminal (which did not contain dense-cored vesicles) was presynaptic to another vesicle-containing profile, including the scalloped central terminal thought to derive from primary afferents. Another population of labeled GAD terminals was found postsynaptic to unlabeled vesicle-containing profiles, including central terminals. These data indicate that inhibitory GABA-ergic controls in the trigeminal nucleus caudalis involve both presynaptic and postsynaptic mechanisms and are probably mediated via direct contacts onto ascending projection neurons, as well as via synaptic contacts onto nociceptive primary afferent fibers. The transmission of nociceptive messages by neurons of the spinal cord dorsal horn and trigeminal nucleus caudalis is subject to a variety of segmental and supraspinal controls. Pharmacological and electrophysiological studies have implicated the biogenic amines serotonin and norepinephrine, and the endogenous opioid peptides enkephalin and dynorphin, in those controls (Basbaum and Fields, 1978, 1984; Basbaum et al., 1983; Basbaum, 1985).(ABSTRACT TRUNCATED AT 400 WORDS)

Transneuronal transport of lectins

Axonal and transneuronal transport of the plant lectins wheat germ agglutinin (WGA), Pisum sativum agglutinin (PSA), Lens culinaris agglutinin (LCA), soybean agglutinin (SBA), peanut agglutinin (PNA), concanavalin A agglutinin (Con A), and Ulex europeus agglutinin (UEA) were examined and compared using an immunocytochemical staining method. WGA, which binds to N-acetylglucosamine and sialic acid carbohydrate residues, and the 3 mannose binding lectins (Con A, PSA and LCA) were found to undergo retrograde transport to the facial nucleus after injection into the facial muscles, and anterograde transport to the optic tectum after injection in the vitreous, and to the spinal trigeminal nucleus caudalis after injection into the mystatial vibrassae. SBA showed a slight tendency to be transported retrogradely, but not in the anterograde direction, whereas UEA and PNA were not axonally transported in any of these systems. All lectins which were transported in the anterograde direction labeled neuronal somata in their respective terminal fields indicating that transneuronal transport had taken place. Axonal and transneuronal transport of the lectins appears to be dependent upon their respective carbohydrate affinities. Transneuronal transport which can be demonstrated for certain lectins indicates that mechanisms exist whereby neurons exchange large molecules which could be involved in mediating trophic and other influences on target cells.

Calcitonin gene-related peptide coexists with substance P in capsaicin sensitive neurons and sensory ganglia of the rat

Immunohistochemical and radioimmunoassay studies revealed that both CGRP- and SP-like immunoreactivity in the caudal spinal trigeminal nucleus and tract, the substantia gelatinosa and the dorsal cervical spinal cord as well as in cell bodies of the trigeminal ganglion and the spinal dorsal root ganglion is markedly depleted by capsaicin which is known to cause degeneration of a certain number of primary sensory neurons. Higher brain areas and the ventral spinal cord were not affected by capsaicin treatment. Furthermore CGRP and substance P-like immunoreactivity were shown to be colocalized in the above areas and to coexist in cell bodies of the trigeminal ganglion and the spinal dorsal root ganglia. It is suggested that CGRP, like substance P, may have a neuromodulatory role on nociception and peripheral cardiovascular reflexes.

Projections of the bed nucleus of the stria terminalis to the mesencephalon, pons, and medulla oblongata in the cat.

Injections of HRP in the nucleus raphe magnus and adjoining medial reticular formation in the cat resulted in many labeled neurons in the lateral part of the bed nucleus of the stria terminalis (BNST) but not in the medial part of this nucleus. HRP injections in the nucleus raphe pallidus and in the C2-segment of the spinal cord did not result in labeled neurons in the BNST. Injections of 3H-leucine in the BNST resulted in many labeled fibers in the brain stem. Labeled fiber bundles descended by way of the medial forebrain bundle and the central tegmental field to the lateral tegmental field of pons and medulla. Dense BNST projections could be observed to the substantia nigra pars compacta, the ventral tegmental area, the nucleus of the posterior commissure, the PAG (except its dorsolateral part), the cuneiform nucleus, the nucleus raphe dorsalis, the locus coeruleus, the nucleus subcoeruleus, the medial and lateral parabrachial nuclei, the lateral tegmental field of caudal pons and medulla and the nucleus raphe magnus and adjoining medial reticular formation. Furthermore many labeled fibers were present in the solitary nucleus, and in especially the peripheral parts of the dorsal vagal nucleus. Finally some fibers could be traced in the marginal layer of the rostral part of the caudal spinal trigeminal nucleus. These projections appear to be virtually identical to the ones derived from the medial part of the central nucleus of the amygdala (Hopkins and Holstege 1978). The possibility that the BNST and the medial and central amygdaloid nuclei must be considered as one anatomical entity is discussed.

The postnatal development of corticotrigeminal projections in the cat.

The postnatal development of corticotrigeminal projections was studied in kittens following 3H-amino acid injections into the face area of the primary somatosensory cortex. Corticofugal axons grow into the brainstem and form the pyramidal tract prenatally. Corticotrigeminal projections begin to develop at the end of the first postnatal week. The earliest corticotrigeminal axons grow out of the pyramidal tract caudally and project into laminae III-V of the spinal trigeminal (Vs) nucleus caudalis. During the second postnatal week, corticotrigeminal axons grow out of the pyramidal tract in a caudal to rostral sequence and project up to the ventromedial borders of Vs-interpolaris, Vs-oralis, and to the principal trigeminal nucleus. Corticotrigeminal axons pause at the periphery of these nuclei for 1-2 days before penetrating the trigeminal neuropil and forming terminal arborizations in a centripetal direction. Coincident with the development of cortical projections to the principal trigeminal nucleus, some of the labeled axons which were in lamina III of Vs-caudalis project into lamina I and terminate. This sequence of development of corticotrigeminal projections closely parallels, albeit at a later time, the sequence of formation of the trigeminal nuclei, suggesting that the temporal sequence of cytogenesis of trigeminal neurons may be a factor which regulates their order of innervation by afferents. Corticotrigeminal projections develop bilaterally and, during the second postnatal week, are relatively equal in density in the ipsilateral and contralateral nuclei. Many of the ipsilateral corticotrigeminal projections are lost, however, after the second postnatal week, so that by the fourth postnatal week, corticotrigeminal projections are mainly contralateral and adultlike in their distribution. It remains to be determined whether the transience of ipsilateral corticotrigeminal projections is due to selective elimination of axon collaterals or to neuronal death.

Cerebellar afferents in the frogs, Rana esculenta and Rana temporaria.

Afferents to the cerebellum in frogs (Rana esculenta, Rana temporaria) were studied by use of retrograde transport of horseradish peroxidase. Following injections restricted to the molecular layer of the cerebellum cell labelling was found in the contralateral inferior olive and the ventral portion of the caudal medullary raphe. Injections involving the granular layer resulted in labelling in the ventral horn of the cervical spinal cord, the caudal spinal trigeminal nucleus, the nucleus caudalis and the medial portion of the nucleus ventralis of the vestibular nerve, the inferior reticular nucleus and the nucleus of the fasciculus longitudinalis medialis. Following larger injections, which may have spread significantly into the cerebellar, secondary gustatory, trigeminal or vestibular nuclei, labelled cell bodies were also found in the nucleus ruber, nucleus solitarius, the rostral spinal trigeminal nucleus and the rostral rhombencephalic reticular formation. It is unclear whether the fibers from these latter areas innervate the cerebellum of the frog, as they do in mammals, or only reach the underlying areas. This situation emphasizes a limitation of the HRP technique when applied to small structures as is often the case in lower vertebrates.

Subcortical auditory and somatosensory afferents to hamster superior colliculus

To determine whether the pattern of superior colliculus (SC) afferents seen in cat is generalizable to other mammalian species, HRP was injected into the SC of twenty hamsters ( Mesocricetus auratus). After reaction with TMB, subcortical structures were examined for labeled perikarya. Although most subcortical afferents to SC were similar in cat and hamster, there were differences in auditory and somatosensory SC innervation. In hamster only two putatively auditory structures showed labeled cells, the external nucleus of inferior colliculus and nucleus of the brachium of the inferior colliculus, whereas in cat additional cells are reported in the dorsal cochlear nucleus, trapezoid and superior olivary nuclei, and nucleus of the lateral lemniscus. Again, in hamster the major trigeminal somatosensory input to SC is from spinal trigeminal nucleus caudalis whereas in cat trigeminal input is reported to be from the principalis and oralis portions of the trigeminal nucleus. Thus the hamster possesses a very restricted auditory input to and a different pattern of somatosensory innervation of the SC relative to the cat.

Brain stem projections to the facial nucleus of the rat.

Horseradish peroxidase was injected into the medial and lateral columns of the facial nucleus of the rat. Following medial injections, cells were labelled by retrograde transport in the ipsilateral spinal trigeminal nucleus (caudalis) both medial vestibular nuclei, contralateral midbrain reticular formation and nucleus of the lateral lemniscus. The periaqueductal grey, interstitial nucleus and nucleus of Darkschewitch were also labelled ipsilaterally. Injections into the lateral column of the facial nucleus labelled the spinal trigeminal nucleus (oralis) and parabrachial nuclei ipsilaterally and the Darkschewitch and red nuclei contralaterally.

Inhibitory actions produced by local electrical stimulation in the caudal spinal trigeminal nucleus in rat

Inhibitory actions induced by local electrical stimulation (LES) on the tooth pulpal afferent activities were investigated in the caudal part of the rat spinal trigeminal nucleus. For the LES, ipsilateral Yin-Hsiang (intrasegmental point) or Ho-Ku (extrasegmental point) was used as a cathodal point which was stimulated electrically by a single pulse of 0.1 msec in duration or by 0.1 msec-pulse train at 45 Hz for 15 min. We found at least three types of inhibitions in the caudal trigeminal nucleus: Type I—this inhibition is the most forceful, caused by naloxone-reversible endogenous opiate system with a slow onset and prolonged aftereffect. This inhibition is presumably postsynaptic action. Type II—this is evoked by postsynaptical acting inhibition and begins within milliseconds after the stimulus is applied. Type III—this inhibition is elicited by presynaptic action and also begins within milliseconds after the onset of the stimulation. Type I and II inhibitions are evoked by stimulating either ultra- or extrasegmental LES points, however, Type III is produced by stimulation of intrasegmental and rarely provoked by extrasegmental point stimulation. Naloxone failed to reverse Type II and III inhibitions. During LES, Type I to III inhibitions co-work for producing the suppressive effect and after the cessation of its stimulation, only Type I inhibition produces the so-called aftereffect of the LES.

Inhibitory mechanisms of the hyper-irritability caused by picrotoxin in the rat

Topically applied norepinephrine, dopamine, serotonin, GABA and glycine, and systemically administered clonidine, l-DOPA (plus carbidopa) and 5-hydroxytryptophan completely suppressed the cutaneous hyper-irritability produced in the trigeminal sensory distribution by picrotoxin overlying the caudal medulla. Cholinergic agents and apomorphine were ineffective. Of the positive compounds, norepinephrine, serotonin and GABA showed the shortest latencies and norepinephrine and serotonin required the lowest concentrations in order to inhibit the hyper-irritability. If l-DOPA (plus carbidopa) was injected after pre-treatment with FLA-63, the effects of l-DOPA did not appear. Similar depression of the hyper-irritability was caused by electrical stimulation of the central gray. The inhibitory effects of stimulation of the central gray was suppressed after administration of tetrabenazine, but again produced markedly by injection of l-DOPA. From these observations it was concluded that the hyper-irritability could be suppressed by serotonergic as well as noradrenergic fibers terminating at the spinal trigeminal nucleus caudalis. The potential clinical use of l-DOPA in patients with hyperesthesia is discussed.

Functional properties of neurons in cat trigeminal subnucleus caudalis (medullary dorsal horn). II. Modulation of responses to noxious and nonnoxious stimuli by periaqueductal gray, nucleus raphe magnus, cerebral cortex, and afferent influences, and effect of naloxone.

Functional properties of neurons in cat trigeminal subnucleus caudalis (medullary dorsal horn). II. Modulation of responses to noxious and nonnoxious stimuli by periaqueductal gray, nucleus raphe magnus, cerebral cortex, and afferent influences, and effect of naloxone.

Functional properties of neurons in cat trigeminal subnucleus caudalis (medullary dorsal horn). I. Responses to oral-facial noxious and nonnoxious stimuli and projections to thalamus and subnucleus oralis.

Functional properties of neurons in cat trigeminal subnucleus caudalis (medullary dorsal horn). I. Responses to oral-facial noxious and nonnoxious stimuli and projections to thalamus and subnucleus oralis.

Changes of the jaw opening reflex activity by electroacupuncture stimulation in rat.

After electroacupuncture stimulation applied to bilateral Ho-Ku points in the rat forepaw, jaw opening reflex to tooth pulp stimulation was fairly suppressed, but that to gingiva, upper lip or lower lip stimulation was scarcely affected. By direct stimulation of afferent sensory pathway in the spinal trigeminal nucleus, jaw opening reflex was also evoked. Suppressive effects of electroacupuncture were more markedly observed when the jaw opening reflex was evoked by stimulating the caudal part of the spinal trigeminal nucleus than when the reflex was evoked by stimulation of the rostral area of the nucleus. One of the main action sites of the electroacupuncture on the jaw opening reflex was the caudal spinal trigeminal nucleus, which is the secondary neuron level in the trigeminal noxious sensory pathway, suggesting that electroacupuncture can provoke the pain suppressive effects strongly in the lower part of the brain with the higher brain function being intact. Therefore, this observation is thought to be well coincident with clinical data that acupuncture produces analgesia without affecting patients' consciousness during surgical operations.

Electroacupuncture suppression of the rat jaw opening response after stimulating the caudal spinal trigeminal nucleus

Suppressive effects of electroacupuncture on the jaw opening responses evoked by stimulation of two areas (anterior and posterior) within the caudal spinal trigeminal nucleus were investigated using lightly anesthetized rats. Electroacupuncture stimulation markedly suppressed the jaw opening responses evoked by stimulating the posterior area, but suppressed only slightly those evoked by stimulating the anterior area.

Three bulbospinal pathways from the rostral medulla of the cat: an autoradiographic study of pain modulating systems

Pain: June 1979 - Volume 6 - Issue 3 - p 384-385 doi: 10.1016/0304-3959(79)90059-9

The origin of brainstem-spinal pathways in the North American opossum (Didelphis virginiana). Studies using the horseradish peroxidase method.

AbstractBrainstem neurons which project to lumbar, thoracic and cervical spinal levels have been identified in the North American opossum by the horseradish peroxidase (HRP) technique. Neurons which relay to all of the levels studied are located within the medullary and pontine reticular formation as well as within the nucleus cuneatus, the nucleus of the tractus solitarius, the lateral reticular nucleus, the medullary and caudal pontine raphe nuclei, the lateral, medial and inferior vestibular nuclei, the nucleus “F,” the nucleus coeruleus, and the nucleus coeruleus, para α, the red nucleus, and the interstitial nucleus of Cajal. The lateral vestibulospinal and rubrospinal systems are topographically organized, although neurons projecting to different cord levels show considerable intermingling. Our material also provides evidence that raphe‐spinal and reticulospinal connections are organized to some degree. Neurons which backfill after cervical and thoracic placements, but not after lumbar injections, are distributed within the caudal spinal trigeminal nucleus, the nucleus intercalatus, the dorsal vagal nucleus, the cuneiform area of Castaldi, the fields of Forel, and the nucleus of Darkschewitsch. Reactive neurons are present within the lateral, dorsal and posterior hypothalamic areas as well as within the periventricular and paraventricular nuclei after thoracic placements and within the superior colliculus after injections within the cervical cord. Additionally, neurons are reactive in the nucleus ambiguus, the interpolar division of the spinal trigeminal nucleus and the rostral division of the oculomotor nucleus (Oswaldo‐Cruz and Rocha‐Miranda, '68) after HRP placements into the third and fourth cervical segments.