Superior Salivatory Nucleus Research Articles

Increased nasal mucosal blood flow, airway resistance and secretion induced by electrical stimulation of the superior salivatory nucleus in cats

Increased nasal mucosal blood flow, airway resistance and secretion induced by electrical stimulation of the superior salivatory nucleus in cats

Rhombomere-specific origin of branchial and visceral motoneurons of the facial nerve in the rat embryo.

The goal of this study was to localize selectively the facial nerve branchial and visceral motoneurons in the rat embryo hindbrain. This was achieved by injecting dextran amines into the peripheral facial nerve on embryos maintained in an artificial cerebrospinal fluid. Sprague-Dawley rat embryos 13, 14, and 15 days old (E13, E14, E15) were obtained by cesarean section. Branchial motoneurons were first labeled at E13. They were close to the midline and migrated from rhombomere (r) 4 toward r5 and r6. By E15, they had migrated caudally and ventrolaterally into the former location of r6. Most of them had reached their "adult" position by E15. Another group of motoneurons, the accessory facial nucleus, was found in r4 at E13 and in corresponding regions at later stages. Visceral motoneurons were labeled from the periphery at all stages. At E13, they were mainly in r5 but also in r2, r3, r4, and r6. At E14, most of them had migrated laterally, and, by E15, they were in the prospective parvocellular reticular formation. They could be divided into two subgroups: a more rostral one with fibers that made loops close to the midline and a more caudal one with fibers that went directly to the exit. The findings presented here show that most branchial and visceral motoneurons of the facial nerve are born in different and specific rhombomeres. Interestingly, developmental genes are expressed specifically in these rhombomeres and could be involved in the genesis of the facial and superior salivatory nuclei.

Parasympathetic excitation of sympathetic innervation after cholinesterase inhibition.

1. Orbital parasympathetic innervation normally provides prejunctional muscarinic inhibition of sympathetic neurotransmission without activation of excitatory muscarinic receptors located on the innervated smooth muscle. The present study examines the role of acetylcholinesterase (AChE) in limiting the effects of parasympathetically released acetycholine to prejunctional receptors. 2. Urethane anaesthetized rats were placed in a stereotaxic frame, and parasympathetic activation was achieved by electrical stimulation (20 Hz, < 2.0 V) of the ipsilateral superior salivatory nucleus. Drugs were administered through a femoral venous cannula. Superior tarsal smooth muscle responses were measured by recording eyelid tension. 3. Parasympathetic stimulation alone caused a small decrease in resting tension; previous studies have shown this to be attributable to attention of resting sympathetic tone. Parasympathetic activation following physostigmine administration, however, evoked a large contractile response. Contractions were resistant to atropine but were blocked by gallamine, guanethidine, and phentolamine. 4. We conclude that AChE inhibition results in conversion of orbital parasympathetic nerve function from inhibition of sympathetic neurotransmission to smooth muscle excitation. This occurs as a result of cholinergic activation of excitatory nicotinic receptors on sympathetic varicosities, which elicit the release of noradrenaline.

Responses of the superior salivatory nucleus neurons to stimulation of the lateral hypothalamic area in the cat.

Responses of the superior salivatory nucleus neurons to stimulation of the lateral hypothalamic area in the cat.

Propagation of Pseudorabies Virus in the Nervous System of the Mouse after Intranasal Inoculation

The propagation of pseudorabies virus (PrV) in the mouse nervous system was studied after intranasal inoculation of a PrV mutant expressing β-galactosidase after insertion of the Escherichia coli Lac-Z gene into the gene encoding the nonstructural, nonessential glycoprotein gG. This allowed rapid detection of infected cells by a single step reaction with the substrate X-gal. The gG-βgal+ mutant behaved like the wild-type Kaplan strain of origin. The incubation period was very short and the animals did not survive more than 52 hr after inoculation. In the nasal cavity, the virus infected almost exclusively the respiratory epithelium. The virus propagated to the nervous system via three neuronal pathways: (i) the trigeminal route, with primary infection in the trigeminal ganglion followed by anterograde transneuronal transfer to the spinal trigeminal nucleus; (ii) the sympathetic route, with a first cycle of replication in the superior cervical ganglion and retrograde transneuronal transfer to sympathetic preganglionic neurons in the intermediolateral nucleus in the spinal cord; and (iii) the parasympathetic route, with primary infection in the pterygopalatine ganglion, followed by retrograde transneuronal transfer and replication in the superior salivatory nucleus. In contrast, the olfactory system was rarely found infected, probably because of the short survival of the animals.

Role of the superior salivatory nucleus in heat loss system in FOK rat

Role of the superior salivatory nucleus in heat loss system in FOK rat

Brain blood flow regulation of the brainstem.

In anesthetized, paralyzed and artificially ventilated rats, the nucleus tractus solitarii (NTS), caudal ventrolateral medullary depressor area (VLDA), and rostral ventrolateral medullary pressor area (VLPA) were chemically stimulated. The roles of these areas on cerebral and spinal cord circulation, the receptor type of the NTS to control cerebral circulation, and the interaction between the VLDA and the VLPA were investigated. The NTS, VLDA, and VLPA have vasoconstrictor effects on the cerebral circulation, respectively. The VLPA has a vasoconstrictor effect on spinal cord circulation. The greater petrosal nerve (GPN) cell group, which is a subgroup of the superior salivatory nucleus, may constitute a parasympathetic cerebrovasodilator center. The NMDA receptors in the NTS may be involved in the control of cerebral circulation. The vasoconstrictive pathway to control cerebral vessels from the VLDA is mediated via the VLPA and the cervical sympathetic nerves. The present results also suggest that there may be a sympathoexcitatory pathway from the VLDA to the VLPA for controlling cerebral vessels and a sympathoinhibitory pathway from the VLDA to the VLPA for controlling systemic vessels. These different roles of the pathways from the VLDA to the VLPA for the different organs may explain the regional differences of the sympathetic nerves activities.

Schrimer test in Parkinson's disease.

We carried out the Schirmer test to measure objectively the amount of lacrimation among 51 clinically diagnosed parkinsonian patients (33 men and 18 women aged 50 to 79 years, mean 64) and 75 age-matched controls (42 men and 33 women aged 50 to 76, mean 62). Whatman No. 2 paper, prepared in precut strips 5mm by 35mm, was placed in the cul-de-sac for five minutes, after which the wetted length of the strip was studied. It was noted that the lacrimation amount decreased in patients with Parkinson's disease compared with controls: the average amount of lacrimation was 3.4 +/- 2.3mm in the former group and 8.1 +/- 6.5mm in the latter group (p < 0.01). We believe that the decrease in the amount of lacrimation is associated with emotional disturbance and autonomic dysfunction, and presume that the lacrimation may be under the control of the basal ganglia which has a connection with the superior salivatory nucleus downward and the limbic system upward.

Nitric oxide-related vasodilator responses to the superior salivatory nucleus stimulation in the cat nasal mucosa

Nitric oxide-related vasodilator responses to the superior salivatory nucleus stimulation in the cat nasal mucosa

In situ hybridization localization of choline acetyltransferase mRNA in adult rat brain and spinal cord

The cellular distribution of choline acetyltransferase (ChAT) mRNA within the adult rat central nervous system was evaluated using in situ hybridization. In forebrain, hybridization of a 35S-labeled rat ChAT cRNA densely labeled neurons in the well-characterized basal forebrain cholinergic system including the medial septal nucleus, diagonal bands of Broca, nucleus basalis of Meynert and substantia innominata, as well as in the striatum, ventral pallidum, and olfactory tubercle. A small number of lightly labeled neurons were distributed throughout neocortex, primarily in superficial layers. No cellular labeling was detected in hippocampus. In the diencephalon, dense hybridization labeled neurons in the ventral aspect of the medial habenular nucleus whereas cells in the lateral hypothalamic area and supramammillary region were more lightly labeled. Hybridization was most dense in neurons of the motor and autonomic cranial nerve nuclei including the oculomotor, Edinger-Westphal, and trochlear nuclei of the midbrain, the abducens, superior salivatory, trigeminal, facial and accessory facial nuclei of the pons, and the hypoglossal, vagus, and solitary nuclei and nucleus ambiguus of the medulla. In addition, numerous cells in the pedunculopontine and laterodorsal tegmental nuclei, the ventral nucleus of the lateral lemniscus, the medial and lateral divisions of the parabrachial nucleus, and the medial and lateral superior olive were labeled. Occasional labeled neurons were distributed in the giantocellular, intermediate, and parvocellular reticular nuclei, and the raphe magnus nucleus. In the medulla, light to moderately densely labeled cells were scattered in the nucleus of Probst's bundle, the medial vestibular nucleus, the lateral reticular nucleus, and the raphe obscurus nucleus. In spinal cord, the cRNA densely labeled motor neurons of the ventral horn, and cells in the intermediolateral column, surrounding the central canal, and in the spinal accessory nucleus. These results are in good agreement with reports of the immunohistochemical localization of ChAT and provide further evidence that cholinergic neurons are present within neocortex but not hippocampus.

Distribution of calcitonin gene-related peptide immunoreactivity in the central nervous system of the frog, Rana esculenta.

The distribution of calcitonin gene-related peptide (CGRP), immunoreactive structures in the central nervous system of the frog, Rana esculenta, was studied using the peroxidase immunohistochemical method. Immunoreactive perikarya were found in all major parts of the brain. In the forebrain, neurons of the septohippocampal formation, the amygdala, the ventromedial and posterocentral thalamic nuclei, and the cerebrospinal fluid contacting neurons in the diencephalic periventricular organ showed immunoreactivity. The pear-shaped neurons of the optic tectum, and perikarya of the oculomotor nucleus in the midbrain were also immunoreactive. In the hindbrain, neurons of the cranial nerve motor nuclei, neurons of the superior vestibular nucleus, giant cells of the reticular formation, and preganglionic parasympathetic neurons of the superior salivatory nucleus were stained. Motoneurons presented immunostaining also in the spinal cord. Immunoreactive fibers were shown to occur in the olfactory tract, the striatum, the tegmentum and the basis mesencephali, the descending tract of the trigeminal nerve, the solitary tract, Lissauer's tract, and the dorsal horn of spinal cord. A comparison of the distribution of CGRP immunoreactivity in the mammalian and amphibian central nervous system revealed that, in relation to the size of the brain, CGRP is more extensively distributed in the amphibian than in the mammalian limbic system.

CNS cell groups projecting to the submandibular parasympathetic preganglionic neurons in the rat: a retrograde transneuronal viral cell body labeling study

The retrograde transneuronal viral tracing method was used to study the CNS nuclei that innervate the parasympathetic preganglionic neurons controlling the submandibular gland in the rat. A genetically engineered β-galactosidase expressing Bartha strain of pseudorabies virus (PRV) was injected into the submandibular gland of rats. After 4 days, PRV infected tissues were reacted with the Bluo-Gal substrate (halogenated indolyl-β- d-galactoside) and labeled cell bodies were identified throughout the brain. In the medulla oblongata, cell body labeling was seen in the superior salivatory nucleus, and throughout the medullary recticular formation as well as in the nucleus of the solitary tract, spinal trigeminal nucleus, and deep cerebellar nuclei. In the pons, PRV labeled neurons were found bilaterally in the locus ceruleus, subceruleus region, and parabrachial complex. In the mesencephalon, labeled cells were found in the Edinger-Westphal nucleus, deep mesencephalic nucleus, and central grey matter. Several hypothalamic regions were labeled including the lateral, perifornical and paraventricular hypothalamic nuclei. In the telecephalon, PRV-positive cell bodies were observed in the substantia innominata, bed nucleus of the stria terminalis and central nucleus of the amygdala. The results suggest that widespread areas of the CNS are involved in control of salivation.

Direct amygdaloid projections to the superior salivatory nucleus: a light and electron microscopic study in the cat

Amygdaloid projections to the superior salivatory nucleus (SSN) were investigated in the cat by using the anterograde and retrograde tracing techniques of horseradish peroxidase (HRP). After HRP injections were made into the lingual nerve, retrogradely labeled SSN neurons were located in the lateral tegmental field medial to the spinal trigeminal nucleus from the middle level of the superior olivary nucleus to the caudal level of the facial nucleus. These labeled neurons, triangular, oval or polygonal in shape, were small to medium-sized (12–29 μm) and formed loosely packed clusters. In further HRP studies, HRP injections were made into the amygdala and in the reticular formation containing the SSN neurons. The results suggested that the SSN receives direct afférents from the central nucleus of the amygdala with ipsilateral predominance. Final proof of such direct connections from amygdala to the SSN can be obtained only by electron microscopic study. Therefore, HRP injections were made into the lingual nerve and in the amygdala in the same animal and electron microscopic observations were carried out on the SSN. It appeared that anterogradely labeled amygdalotegmental fibers formed axosomatic and axodendritic synaptic contacts with retrogradely labeled SSN neurons.

Descending projections from the hypothalamic paraventricular nucleus to the A5 area, including the superior salivatory nucleus, in the rat

The descending projection of the hypothalamic paraventricular nucleus (PVN) to the A5 area was elucidated using a technique that combines retrograde labeling with horseradish peroxidase (HRP), anterograde labeling with PHA-L (Phaseolus vulgaris leucoagglutinin and immunohistochemistry for dopamine-beta-hydroxylase (DBH). Following an iontophoretic injection of PHA-L into the PVN, HRP was applied to the greater petrosal nerve. Frozen sections of the hypothalamus and the caudal pons were first treated according to a protocol for HRP histochemistry using tetramethylbenzidine with cobalt-enhanced diaminobenzidine, and then they were processed for displaying PHA-L, and then for DBH immunohistochemistry. PHA-L labeled fibers from the PVN were observed in a ventrolateral part of the pontine reticular formation corresponding to the A5 area, where they give rise to a dense network around the cells of origin of the greater petrosal nerve (GPN cells) and DBH-positive cells. Terminals or varicosities labeled with PHA-L were preferentially observed around the somata of GPN cells, suggesting direct contact. However, apparent contact between both elements was hardly ever observed. On the other hand, terminals or varicosities were occasionally observed in close relation to DBH-positive cells. These results suggest that descending fibers of the PVN project more strongly to GPN cells than to DBH-positive cells. The relationship of this fiber pathway to control of the secretomotor or cardiovascular systems is discussed.

CNS projections to the pterygopalatine parasympathetic preganglionic neurons in the rat: a retrograde transneuronal viral cell body labeling study

The retrograde transneuronal viral cell body labeling method was used to study the CNS nuclei that innervate the parasympathetic preganglionic neurons which project to the pterygopalatine ganglion. Small injections of a suspension of pseudorabies virus (PRV) were made in the pterygopalatine ganglion of rats and after 4 days their brains were processed for immunohistochemical detection of PRV. Some of the tissues were stained with a dual immunofluorescence method that permitted the visualization of PRV and neurotransmitter enzyme or serotonin immunoreactivity in the same cell. Retrograde cell body labeling was detected in the ipsilateral ventrolateral medulla oblongata in the region that has been termed the superior salivatory nucleus. This area was the same region that was retrogradely labeled after Fluoro-Gold dye injections in the pterygopalatine ganglion. Retrograde transneuronally infected cell bodies that provide putative afferent inputs to the pytergopalatine parasympathetic preganglionic neurons were mapped throughout the brain. In the medulla oblongata, transneuronally labeled neurons were seen in the nucleus tractus solitarii, dorsomedial part of the spinal trigeminal nucleus and gigantocellular reticular nucleus. In most experiments, some A1 catecholamine cells and serotonin neurons of the raphe magnus, raphe pallidus, raphe obscurus, and parapyramidal nuclei were labeled. In the pons, labeled cells were found in the parabrachial nucleus, A5 catecholamine cell group, and non-catecholamine part of the subcoeruleus region. In the midbrain, cell body labeling was located in the central gray matter and retrorubral field. In the diencephalon, labeling was found mainly in the hypothalamus. The areas included the lateral hypothalamic area, lateral preoptic area, dorsomedial and paraventricular hypothalamic nuclei, and ventral zona incerta. Contralateral second order cell body labeling was seen in the tuberomammillary nucleus of the hypothalamus. Some of these cells were histidine decar☐ylase-immunoreactive. In the forebrain, the bed nucleus of the stria terminalis, substantia innominata, and an area of the cerebral cortex called the amygdalopiriform transition zone were labeled.

Percutaneous cordotomy for malignant pain

The retrograde transneuronal viral tracing method was used to study the CNS nuclei that innervate the parasympathetic preganglionic neurons controlling the submandibular gland in the rat. A genetically engineered β-galactosidase expressing Bartha strain of pseudorabies virus (PRV) was injected into the submandibular gland of rats. After 4 days, PRV infected tissues were reacted with the Bluo-Gal substrate (halogenated indolyl-β-d-galactoside) and labeled cell bodies were identified throughout the brain. In the medulla oblongata, cell body labeling was seen in the superior salivatory nucleus, and throughout the medullary recticular formation as well as in the nucleus of the solitary tract, spinal trigeminal nucleus, and deep cerebellar nuclei. In the pons, PRV labeled neurons were found bilaterally in the locus ceruleus, subceruleus region, and parabrachial complex. In the mesencephalon, labeled cells were found in the Edinger-Westphal nucleus, deep mesencephalic nucleus, and central grey matter. Several hypothalamic regions were labeled including the lateral, perifornical and paraventricular hypothalamic nuclei. In the telecephalon, PRV-positive cell bodies were observed in the substantia innominata, bed nucleus of the stria terminalis and central nucleus of the amygdala. The results suggest that widespread areas of the CNS are involved in control of salivation.

Effects of atropine injection on food-associated drinking in rats with superior salivatory nucleus lesions

The neuropharmacological mechanisms involved in the prandial drinking pattern seen in rats with superior salivatory nucleus lesions + parotidectomy were investigated with behavioral methods. Results showed that the administration of low doses (0.1 mg/kg body wt) of atropine in lesioned rats potentiated previously established prandial drinking. Higher doses of atropine (1.0 mg/kg), however, were required to induce a similar degree of prandiality in control rats (parotidectomy alone). These findings suggest that the salivatory nucleus lesions affected a cholinergic brainstem-salivary gland system involved in the neural control of food-associated drinking.

Convergence of excitatory inputs from the chorda tympani, glossopharyngeal and vagus nerves onto superior salivatory nucleus neurons in the cat

Superior salivatory nucleus (SSN) neurons were identified by antidromic spike responses to stimulation of the chorda tympani nerve, and were tested to stimulation of the ipsilateral chorda tympani, glossopharyngeal, vagus and lingual nerves in urethane-chloralose anesthetized cats. In 48 SSN neurons identified, 33 (69%) responded with spikes to stimulation of at least one of these nerves, and 24 (50%) were excited with inputs from more than one stimulated nerve. The mean latencies of the reflex responses to stimulation of the chorda tympani, glossopharyngeal, vagus or lingual nerve were 13.2, 18.9, 24.6 or 11.4 ms, respectively.

The human brain at stage 17, including the appearance of the future olfactory bulb and the first amygdaloid nuclei.

The growth of the cerebral hemispheres rostrally and caudodorsally brings about a deepening of the interlongitudinal fissure, in which blood capillaries for the future choroid plexus develop. Accumulation of mesenchyme basally presages the formation of the nasal septum. The olfactory bulb and tubercle become outlined. The three main areas of the telencephalon, future archi-, paleo-, and neocortex, can be recognized. The amygdaloid body, which is related to the medial ventricular eminence, contains either one or two nuclei. Nerve fibres from the olfactory tubercle arrive and pass through the amygdaloid area. The first indication of a septal nucleus is recognizable. The lateral ventricular eminence is present but not pronounced. The hemispheric stalk joins the cerebral hemispheres to the ventral thalamus and to the diencephalic part of the medial ventricular eminence. The beginning of the future choroid plexus consists in the formation of blood vessels and necrotic changes in the roof of the telencephalon medium and in rostral growth of the anterior choroid artery. Necrotic processes in the future choroid epithelium are now localized at the periphery of the still multilaminar tissue. The sulcus medius and zona intrathalamica delimit the dorsal from the ventral thalamus. The dimesencephalic borderline passes through the commissural fibres in the roof: the rostral part of the commissure is the posterior commissure, the caudal part, the commissure of the superior colliculi. In the mesencephalon, the red nucleus has a laterorostral position with regard to the nucleus of the oculomotor nerve. The cells of the locus coeruleus are well distinguishable. The gustatory fibres begin to separate from the common afferent tract as the tractus solitarius. Inferior and superior salivatory nuclei are delineated.

Gustatory innervation in the rabbit: central distribution of sensory and motor components of the chorda tympani, glossopharyngeal, and superior laryngeal nerves.

Although rabbits have been used extensively in neurophysiological studies of the gustatory system, there is little information about the anatomical organization of taste in this species. Afferent and efferent central connections of three nerves innervating oral or laryngeal taste buds in the rabbit, including the chorda tympani (CT), the lingual-tonsillar branch of the glossopharyngeal (IX), and the superior laryngeal nerve (SLN), were traced by means of horseradish peroxidase neurohistochemistry. After entering the brainstem, most afferent fibers of CT, IX, and SLN turned caudally in the solitary tract, with fibers of the CT terminating in the nucleus of the solitary tract from 1.0 mm rostral to 3.8 mm caudal to the caudal border of the dorsal cochlear nucleus. There was terminal label from the CT also in the principal trigeminal nucleus. There was terminal label from the CT also in the principal trigeminal nucleus and the oral and intermediate divisions of the spinal trigeminal nucleus. Preganglionic parasympathetic cell bodies of the superior salivatory nucleus were labeled retrogradely in the reticular formation ventral to the rostral pole of the solitary nucleus. Afferent fibers of the IXth nerve terminated in the solitary nucleus from 0.6 mm rostral to 5.0 mm caudal to the caudal border of the dorsal cochlear nucleus. There were also labeled terminals in the principal trigeminal nucleus and in all three divisions of the spinal trigeminal nucleus. Cell bodies composing the inferior salivatory nucleus were labeled in and around the solitary nucleus and subadjacent reticular formation just rostral to the caudal border of the dorsal cochlear nucleus. There were also a few lightly labeled cells within the nucleus ambiguus at its most rostral extent. Afferent fibers of the SLN terminated in the solitary nucleus from 1.2 to 6.8 mm caudal to the dorsal cochlear nucleus. There was also some terminal label in the intermediate and caudal divisions of the spinal trigeminal nucleus. Many cells were retrogradely labeled in the nucleus ambiguus following application of HRP to the SLN and a few cells were labeled in and around the solitary nucleus just caudal to the dorsal cochlear nucleus. These three nerves show an overlapping rostral to caudal distribution of afferent input within the nucleus of the solitary tract that may be related to their gustatory and visceral functions.