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Effects of peripheral nerve ligation on expression of μ-opioid receptor in sensory ganglion neurons: an immunohistochemical study in dorsal root and nodose ganglion neurons of the rat

The present study was attempted to examine if mu-opioid receptor (MOR) might be transported by axonal flow peripherally through peripheral axons of somatic sensory ganglion neurons. After unilateral ligation of the sciatic nerve or the vagus nerve distal to the dorsal root ganglion (DRG) or nodose ganglion (NG), MOR-like immunoreactivity (MOR-LI) of neuronal cell bodies in the DRG of the fourth and fifth lumbar nerves, NG, Ambiguus Nucleus (Amb) and dorsal motor Nucleus of the vagus nerve (DMV) on the side of the ligation was apparently reduced within 1 week after the nerve ligation. However, within 24 h after the nerve ligation, a transient enhancement of MOR-LI was observed in cell bodies of DRG neurons, sciatic nerve stump proximal to the ligature, and cell bodies of NG neurons on the side of the ligation; such a transient enhancement of MOR-LI was not detected in the Amb and DMV. The results suggest that MOR undergoes centrifugal axonal flow in peripheral axons of somatic and visceral sensory ganglion neurons, and that MOR synthesis in sensory ganglion neurons is vulnerable to damage of the peripheral axons.

the sites of origin and termination of afferent and efferent components in the lingual and pharyngeal branches of the glossopharyngeal nerve in the japanese monkey macaca fuscata

Abstract Afferent and efferent components in the lingual and pharyngeal branches of the glossopharyngeal nerve (Li and Ph) of the Japanese monkey ( Macaca fuscata ) were examined. After injecting wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) unilaterally into the central cut end of the Li and Ph, or into the stylopharyngeal muscle, labeled neuronal cell bodies and terminal labeling were observed in the medulla oblongata, peripheral ganglia of the glossopharyngeal and vagus nerves, and cervical ganglia of the sympathetic trunk. The following conclusions were deduced from the results. The Li contains efferent fibers from the inferior salivatory Nucleus, and superior cervical ganglion. The afferent fibers in the Li are composed mainly of peripheral processes of ganglion neurons in the superior and petrous ganglia of the glossopharyngeal nerve, and additionally of those of ganglion neurons in the jugular ganglion of the vagus nerve. The afferent fibers in the Li terminate mainly in the lateral division of the Nucleus of the solitary tract, and additionally in the dorsal aspect of the lateral marginal region of the interpolar spinal trigeminal Nucleus. The Ph is mainly composed of efferent fibers from the Ambiguus Nucleus and superior cervical ganglion; only a small number of afferent fibers from the sensory ganglia of the glossopharyngeal and vagus nerves are contained in the Ph. Stylopharyngeal motoneurons are distributed in the retrofacial part of the Ambiguus Nucleus.

Localization of μ-opioid receptor-like immunoreactivity in the central components of the vagus nerve : A light and electron microscope study in the rat

Abstract μ-Opioid receptor, the opioid receptor that shows the highest affinity for morphine, appears to induce a variety of side-effects, at least partly, directly through the μ-opioid receptor on neurons constituting the autonomic part of the vagus nerve. Thus, in the present study, location of μ-opioid receptor-like immunoreactivity in the central components of the autonomic part of the vagus nerve was examined in the rat. The intense immunoreactivity was observed light microscopically in the neuropil of the commissural subNucleus and the dorsal part of the medial subNucleus of the Nucleus of the solitary tract, and in the neuropil of the rostral half of the Ambiguus Nucleus. The immunoreactivity was moderate in the neuropil of the rostral and lateral subnuclei and ventral part of the medial subNucleus of the Nucleus of the solitary tract, and weak in the neuropil of the dorsal motor Nucleus of the vagus nerve. In the nodose ganglion, many neurons of various sizes (17–48 μm in soma diameter) showed moderate immunoreactivity. After unilateral vagotomy at a level proximal to the nodose ganglion, the immunoreactivity in the ipsilateral Ambiguus Nucleus was apparently reduced within 48 h of the operation, and completely disappeared by the seventh day after the operation. In the Nucleus of the solitary tract and dorsal motor Nucleus of the vagus nerve, the reduction of immunoreactivity after the ganglionectomy was detectable on the fourth day after the operation, and became readily apparent by the seventh day after the operation; the immunoreactivity, none the less, still remained on the 10th day after the operation. Electron microscopically, the immunoreactivity in the Ambiguus Nucleus was seen mainly on dendritic profiles and additionally on somatic ones; no immunoreactivity was detected in axonal profiles. The immunoreactivity in the dorsal motor Nucleus of the vagus nerve was observed only on dendritic profiles. The immunoreactivity in the Nucleus of the solitary tract was seen on axonal and dendritic profiles, but not on somatic profiles. The immunoreactive axon terminals in the Nucleus of the solitary tract were filled with spherical synaptic vesicles and made asymmetric synapses with dendritic profiles. The results indicate that the μ-opioid receptor in the central components of the autonomic part of the vagus nerve is located on dendrites and cell bodies of efferent neurons in the Ambiguus, on dendrites of efferent neurons in the dorsal motor Nucleus, and on axons which arise from nodose ganglion neurons and terminate in the Nucleus of the solitary tract. The receptors on these structures may constitute the targets of enkephalin-containing and β-endorphin-containing afferent axons arising from brainstem neurons. The receptors on the axon terminals of nodose ganglion neurons may be involved in regulation of the release of neurotransmitters and/or neuromodulators.

Termination of trigeminal primary afferents on glossopharyngeal-vagal motoneurons: possible neural networks underlying the swallowing phase and visceromotor responses of prey-catching behavior.

Prey-catching behavior (PCB) of the frog consists of a sequence of coordinated activity of muscles which is modified by various sensory signals. The aim of the present study was, for the first time, to examine the involvement of the trigeminal afferents in the swallowing phase of PCB. Experiments were performed on Rana esculenta, where the trigeminal and glossopharyngeal (IX)-vagus (X) nerves were labeled simultaneously with different fluorescent dyes. Using confocal laser scanning microscope, close appositions were detected between the trigeminal afferent fibers and somatodendritic components of the IX-X motoneurons of the Ambiguus Nucleus (NA). Neurolucida reconstruction revealed spatial distribution of the trigeminal afferents in the functionally different parts of the NA. Thus, the visceromotor neurons supplying the stomach, the heart and the lung received about two third of the trigeminal contacts followed by the pharyngomotor and then by the laryngomotor neurons. On the other hand, individual motoneurons responsible for innervation of the viscera received less trigeminal terminals than the neurons supplying the muscles of the pharynx. The results suggest that the direct contacts between the trigeminal afferents and IX-X motoneurons presented here may be one of the morphological substrate of a very quick response during the swallowing phase of PCB. Combination of direct and indirect trigeminal inputs may contribute to optimize the ongoing motor execution.

Vestibular afferents to the motoneurons of glossopharyngeal and vagus nerves in the frog, Rana esculenta.

The aim of this work was to study whether the vestibular afferent fibers establish direct connections with the motoneurons of glossopharyngeal and vagus nerves of the frog, Rana esculenta. In anaesthetized animals the vestibulocochlear nerve and the common root of glossopharyngeal-vagus and accessory (IX-X-XI) nerves were simultaneously labeled with fluorescein dextran amine (vestibulocochlear nerve) and tetramethylrhodamine dextran amine (IX-X-XI). With a confocal laser scanning microscope we could detect close appositions between the vestibular afferent fibers and somatodendritic components of the general and special visceral motoneurons of the Ambiguus Nucleus of IX-X nerves. The direct impulse transmission may provide a quick and immediate response of cardiovascular and gastrointestinal system upon body displacement.

Organization of the Ambiguus Nucleus in the frog (Rana esculenta)

The common root of the glossopharyngeal, vagal, and accessory nerves and the individual branches of the vagus complex were labeled with cobalt, and the organization of the Ambiguus Nucleus was studied. The cell column labeled through the common root extended from the upper part of the medulla to the rostral spinal cord over a distance of about 3,500 μm. The labeling of individual branches revealed four subdivisions. 1) The pharyngomotor subdivision occupied the rostral 800 μm of the cell column. It gave origin to the innervation of the pharyngeal muscles. 2) The visceromotor subdivision, consisting of small and medium-sized cells labeled by way of the visceral branches of the vagus, was found in the rostrocaudal extent of the medulla. 3) The laryngomotor subdivision extended in the obex region over a distance of more than 1,000 μm. It supplied the sphincter muscles of the larynx. The dilator laryngeal muscle was represented in the rostral part of the visceromotor subdivision. 4) The accessory nerve subdivision was located in the lower medulla and the rostral spinal cord.

From the results, the following conclusions are drawn. 1) The basic organization of the frog Ambiguus Nucleus is comparable to that of the rat, differences in nuclear organization reflecting differences in peripheral structures. 2) The cytoarchitectonic structure of the four subdivisions innervating different peripheral targets characteristically differ from each other. 3) On the basis of its characteristic neuronal morphology, the accessory nerve Nucleus is regarded as an independent structure. © 1996 Wiley-Liss, Inc.

Effects of peripheral nerve ligation on expression of μ-opioid receptor in sensory ganglion neurons: an immunohistochemical study in dorsal root and nodose ganglion neurons of the rat

The present study was attempted to examine if mu-opioid receptor (MOR) might be transported by axonal flow peripherally through peripheral axons of somatic sensory ganglion neurons. After unilateral ligation of the sciatic nerve or the vagus nerve distal to the dorsal root ganglion (DRG) or nodose ganglion (NG), MOR-like immunoreactivity (MOR-LI) of neuronal cell bodies in the DRG of the fourth and fifth lumbar nerves, NG, Ambiguus Nucleus (Amb) and dorsal motor Nucleus of the vagus nerve (DMV) on the side of the ligation was apparently reduced within 1 week after the nerve ligation. However, within 24 h after the nerve ligation, a transient enhancement of MOR-LI was observed in cell bodies of DRG neurons, sciatic nerve stump proximal to the ligature, and cell bodies of NG neurons on the side of the ligation; such a transient enhancement of MOR-LI was not detected in the Amb and DMV. The results suggest that MOR undergoes centrifugal axonal flow in peripheral axons of somatic and visceral sensory ganglion neurons, and that MOR synthesis in sensory ganglion neurons is vulnerable to damage of the peripheral axons.

Localization of μ-opioid receptor-like immunoreactivity in the central components of the vagus nerve : A light and electron microscope study in the rat

Abstract μ-Opioid receptor, the opioid receptor that shows the highest affinity for morphine, appears to induce a variety of side-effects, at least partly, directly through the μ-opioid receptor on neurons constituting the autonomic part of the vagus nerve. Thus, in the present study, location of μ-opioid receptor-like immunoreactivity in the central components of the autonomic part of the vagus nerve was examined in the rat. The intense immunoreactivity was observed light microscopically in the neuropil of the commissural subNucleus and the dorsal part of the medial subNucleus of the Nucleus of the solitary tract, and in the neuropil of the rostral half of the Ambiguus Nucleus. The immunoreactivity was moderate in the neuropil of the rostral and lateral subnuclei and ventral part of the medial subNucleus of the Nucleus of the solitary tract, and weak in the neuropil of the dorsal motor Nucleus of the vagus nerve. In the nodose ganglion, many neurons of various sizes (17–48 μm in soma diameter) showed moderate immunoreactivity. After unilateral vagotomy at a level proximal to the nodose ganglion, the immunoreactivity in the ipsilateral Ambiguus Nucleus was apparently reduced within 48 h of the operation, and completely disappeared by the seventh day after the operation. In the Nucleus of the solitary tract and dorsal motor Nucleus of the vagus nerve, the reduction of immunoreactivity after the ganglionectomy was detectable on the fourth day after the operation, and became readily apparent by the seventh day after the operation; the immunoreactivity, none the less, still remained on the 10th day after the operation. Electron microscopically, the immunoreactivity in the Ambiguus Nucleus was seen mainly on dendritic profiles and additionally on somatic ones; no immunoreactivity was detected in axonal profiles. The immunoreactivity in the dorsal motor Nucleus of the vagus nerve was observed only on dendritic profiles. The immunoreactivity in the Nucleus of the solitary tract was seen on axonal and dendritic profiles, but not on somatic profiles. The immunoreactive axon terminals in the Nucleus of the solitary tract were filled with spherical synaptic vesicles and made asymmetric synapses with dendritic profiles. The results indicate that the μ-opioid receptor in the central components of the autonomic part of the vagus nerve is located on dendrites and cell bodies of efferent neurons in the Ambiguus, on dendrites of efferent neurons in the dorsal motor Nucleus, and on axons which arise from nodose ganglion neurons and terminate in the Nucleus of the solitary tract. The receptors on these structures may constitute the targets of enkephalin-containing and β-endorphin-containing afferent axons arising from brainstem neurons. The receptors on the axon terminals of nodose ganglion neurons may be involved in regulation of the release of neurotransmitters and/or neuromodulators.

immunohistochemical localization of substance p receptor in the central nervous system of the adult rat

In an attempt to reveal the function sites of substance P (SP) in the central nervous system (CNS), the distribution of SP receptor (SPR) was immunocytochemically investigated in adult rat and compared with that of SP-positive fibers. SPR-like immunoreactivity (LI) was mostly localized to neuronal cell bodies and dendrites. Neurons with intense SPR-LI were distributed densely in the cortical amygdaloid Nucleus, hilus of the dentate gyrus, locus ceruleus, rostral half of the Ambiguus Nucleus, and intermediolateral Nucleus of the thoracic cord; moderately in the caudatoputamen, Nucleus accumbens, olfactory tubercle, median, pontine, and magnus raphe nuclei, laminae I and III of the caudal subNucleus of the spinal trigeminal Nucleus, and lamina I of the spinal cord; and sparsely in the cerebral cortex, basal Nucleus of Meynert, claustrum, gigantocellular reticular Nucleus, and lobules IX and X of the cerebellar vermis. Neurons with weak to moderate SPR-LI were distributed more widely throughout the CNS. The regional patterns of distribution of SPR-LI were not necessarily the same as those of SP-positive fibers. The entopedunucular Nucleus, substantia nigra, and lateral part of the interpeduncular Nucleus showed intense SP-LI but displayed almost no SPR-LI. Conversely, the hilus of the dentate gyrus, anterodorsal thalamic Nucleus, central Nucleus of the inferior colliculus, and dorsal tegmental Nucleus showed intense to moderate SPR-LI but contained few axons with SP-LI. These findings confirmed the presence of the “mismatch” problem between SP and SPR localizations. However, the distribution of SPR-LI was quite consistent with that of the SP-binding activity, which has been studied via autoradiography. This indicates that the sites of SPR-LI revealed in the present study represent most, if not all, sites of SP-binding activity.