Electrophysiological monitoring of pain afferent pathway of the trigeminal nerve and its functional plasticity in response to occlusal interference in rats / 南方医科大学学报

OBJECTIVE@#To observe the effect of occlusal interference on the afferent pathway of the trigeminal nerve and neuronal excitability in the trigeminal subnucleus caudalis (SPVC) of rats by electrical stimulation of the trigeminal ganglion (TG) and extracellular recordings of SPVC activities.@*METHODS@#Twenty male Wistar rats were randomly divided into control group and model group (=10). In the model group, occlusal interference for 30 consecutive days was induced using light-cured flowable resin on the right maxillary molars. During occlusal interference, the pain sensitivity was scored with von Frey Fibers in the masseter. Simultaneous recordings of electrical activities from the SPVC, electrocardiogram, body temperature and electromyogram of the breath muscles of the anesthetized rats were performed, and the responses evoked by electrical stimulation of the TG were analyzed.@*RESULTS@#Compared with the control rats, the rats in the model group showed significantly increased pain sensitivity scores ( 0.05). Train stimulation (0.2 ms, 1 mA, 30 s, 100 Hz) of the TG significantly increased the discharge frequency of the SPVC only in the rats in the model group ( < 0.05).@*CONCLUSIONS@#The functional activities of the pain afferent pathway of the trigeminal nerve can be electrophysiologically monitored by electrical stimulation of the TG and extracellular recordings of SPVC activities in rats. Occlusal interference can increase the excitability of the neurons in the SPVC and enhance their sensitivities to TG afferent activation, suggesting the neural plasticity of the pain afferent pathway.

Isolated Unilateral Adduction Paresis of the Right Eye Due to a Contusion in the Subnucleus of Oculomotor Nerve.

In this report we present a 45 year old man with horizontal diplopia following minor head trauma. Neurological examination was normal except for unilateral adduction paresis of the right eye. Brain magnetic resonance imaging (MRI) revealed a contusion area 7 mm in diameter at the inferiorposterior portion of the mesencephalon. We thought that this contusion affected the sub-nucleus of oculomotor nerve and caused isolated adduction paresis of the right eye. This relatively rare entity is discussed in the light of the available literature.

Expression of KA1 kainate receptor subunit in the substantia gelatinosa of the trigeminal subnucleus caudalis in mice

The KA1 kainate receptor (KAR) subunit in the substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) has been implicated in the processing of nociceptive information from the orofacial region. This study compared the expression of the KA1 KAR subunit in the SG of the Vc in juvenile, prepubescent and adult mice. RT-PCR, Western blot and immunohistochemistry analyses were used to examine the expression level in SG area. The expression levels of the KA1 KAR subunit mRNA and protein were higher in juvenile mice than in prepubescent or adult mice. Quantitative data revealed that the KA1 KAR subunit mRNA and protein were expressed at levels approximately two and three times higher, respectively, in juvenile mice than in adult mice. A similar expression pattern of the KA1 KAR subunit was observed in an immunohistochemical study that showed higher expression in the juvenile (59%) than those of adult (35%) mice. These results show that the KA1 KAR subunits are expressed in the SG of the Vc in mice and that the expression level of the KA1 KAR subunit decreases gradually with postnatal development. These findings suggest that age-dependent KA1 KAR subunit expression can be a potential mechanism of age-dependent pain perception.

Thoracic Vagal Ganglion and Referred Craniofacial Pain: a Case Report and Review / Ganglio Torácico Vagal y Dolor Craneofacial Referido: Reporte de Caso y Revisión

The presence of a ganglion-like tumefaction is reported in the mediastinal course of the right vagus nerve at Tl level in a cadaver in the Universidad Industrial de Santander's morphology laboratory. The vagal ganglion was located next to hyperplasic lymphoid nodes in para-tracheal and tracheal-bronchial levels, agglomerating in a large lymphoid mass in the carina and the pulmonary hilum. Anatomical-pathological study revealed a marked, diffusely distributed, predominantly histo-lymphocyte mixed inflammation, separating the epineurium, producing lysis of the vagus nerve fibers. This finding showed the degeneration of this cranial par by mediastinal pathology. This provided a possible explanation for the physiopathology of pain referring to the head and neck in inflammatory or neoplastic pathology involving compression and degeneration by inflammatory infiltration of the vagus nerve. Pons-medullar trigeminal afferent tracts and connectivity, supra-spinal pathways for processing somatic-visceral pain, possible somatic-vegetative responses and the integration of the trigeminal system in the physiology of pain concerning the vagus nerve are all discussed.

Se reporta la presencia de una tumefacción a manera de "ganglio" en el trayecto mediastínico del nervio vago derecho, a nivel de TI, en un cadáver en el Laboratorio de Morfología de la Universidad Industrial de Santander, Colombia. El "ganglio" vagal se encuentra adyacente a nodos linfoides hiperplásicos, en niveles para-traqueales y tráqueo-bronquiales que se aglomeran en una gran masa linfoide a la altura de la carina e hilio pulmonar. En el estudio anatomopatológico, se encontró marcado proceso inflamatorio mixto de predominio histo-linfocitario el cual se distribuye de manera difusa separando el epineuro y produciendo lisis de las fibras del nervio vago. Este hallazgo muestra la degeneración de este par craneal por patologías a nivel mediastínico. Esto brinda una posible explicación de la fisiopatología del dolor referido a cabeza y cuello, en patologías inflamatorias o neoplásicas que involucran la compresión y degeneración por infiltración inflamatoria del nervio vago. Se discute los tractos y la conectividad de las aferencias vagales a nivel ponto-medular, las vías supraespinales para el procesamiento del dolor sómato-visceral, las posibles respuestas sómato-vegetativas y la integración del sistema trigeminal en la fisiología del dolor en el nervio vago.

Mechanisms of Depressor Effect of Norepinephrine Injected into Subnucleus Commissuriu of Nucleus Solitarius Tractus in Rabbits / 华中科技大学学报（医学）（英德文版）

Summary: This experiment aimed to investigate the effect of adrenergic system in the subnucleus commissuriu of nucleus solitrius tractus (CNTS) on renal nerve discharges. Norepinephrine (NE) was microinjected into the CNTS of rabbits and mean arterial blood pressure (MAP) and renal nerve discharges (FRND) were synchronously recorded. The results indicated that (1) microinjection of norepinephine into the CNTS of rabbit could significantly attenuate the frequency of renal nerve discharge, and at the same time decrease markedly the mean arterial pressure. (2) Microinjection of 0.3 nmol yohimbin into CNTS had no significant influence on FRND and MAP, but could attenuate and even reverse the effects of NE on FRND and MAP. These results suggest that microinjection of NE into CNTS may activate the alpha-adrenorecptor located in CNTS and secondarily produce a depressor effect by attenuating the activity of peripheral sympathetic nervous system.

Study on afferent projections from the abducens nucleus to the contralateral medial rectus subnucleus of the oculomotor nucleus in the rat / 重庆医科大学学报

Objective: To investigate afferent projections from the abducens nucleus to the contralateral medial rectus subnucleus of the oculomotor nucleus in rats.Methods:The means of retrograde hoseradish peroxidase tracing was used.Results:The internuclear neurons in the abducens nucleus were divided into two subgroups,the ventromedial and the ventrolateral ones. The axons of the internuclear nurons crossed the midline,ascended in the contralateral medial longitudinal fasciculus and intermediated exclusively in the contralateral medial rectus subgroups.Conclusion:The results imply that the internuclear meurons could play a major role in conjugate horizontal eye movement.

An Immunohistochemical and Immunoelectron Microscopic Study of Distribution of Neuropeptide Y in the Cat Spinal Trigeminal Subnucleus Caudalis after Pulpectomy / 대한해부학회지

The purpose of this study was to investigate the distribution of neuropeptide Y (NPY) in the cat spinal trigeminal subnucleus caudalis following pulpectomy of mandibular premolars and molar by means of an immunohistochemical and immunoelectron microscopic study. The animals were divided into normal and experimental group which were sacrificed at 14 days after pulpectomy. The results were as follows; 1. On the light microscopic observation of the spinal trigeminal subnucleus caudalis in normal group, NPY-immunoreactivity (IR) was weak within lamina I and lamina II outer. In pulpectomy group, NPY-IR was strong and appeared to extend into lamina I and lamina II inner at 14 days. 2. On the immunoelectron microscopic observation of the spinal trigeminal subnucleus caudalis in normal group, NPY-IR was revealed in axon terminals, dendrites, myelinated axons and unmyelinated axons. NPY-IR was associated with membrane structures within microtubules, synaptic vesicles, outer membrane of mitochondria and inner surface of the axolemma. In NPY-immunoreactive structure, there was a small amount of DAB precipita-tions. 3. On the immunoelectron microscopic observation of the spinal trigeminal subnucleus caudalis at 14 days in pulpectomy group, the number of NPY-immunoreactive axon terminals, dendrites, myelinated axons and unmyelinated axons was increased than normal group. DAB precipitations in NPY-immunoreactive structure was increased than normal group. Some NPY-immunoreactive axon terminal formed synaptic glomerulus and axoaxonic synapse. 4. The results indicate that NPY-IR was increased in the spinal trigeminal subnucleus caudalis after pulpectomy, and it is speculated that the increased NPY by injury of peripheral nerve may participate in the processing of nociception.

PARVALBUMIN-EXPRESSING NEURONS ON THE CENTRAL PATHWAY OF THE TRIGEMINAL PROPRIOCEPTIVE SENSATION OF THE RAT: A DOUBLE LABELING STUDY / 神经解剖学杂志

Previous studies showed that the Vodm-LRF-including the dorsomedial part of the subnucleus oralis of the spinal trigeminal nucleus and its adjacent lateral reticular formation--contained the second-order neurons on the central pathway of the trigeminal proprioceptive sensation of the rat and the "zone-shaped area"-including the caudolateral part of the supratrigeminal nucleus (Vsup-CL). The dorsomedial part of principal sensory trigeminal nucleus (Vpdm) and two newly found nuclei: the areaventral to the motor trigeminal nucleus (AVM) and the area dorsal to the superior olivary nucleus (ADO)-contained the third order neurons of this pathway. Parvalbumin (PV) is one of the calcium-binding proteins, In this pathway, many PV-like immunoreactive (PV-LI) neurons were observed in Vodm LRF and the "zone-shaped arena", hut there has been no reports so far regarding whether these PV-LI neurons are projection neurons responsible for the transmission of proprioceptive information or the interneurons serving the modulatory function, in the present study, our aim was to solve the problem by a double labeling study by using retrograde tracing method combined with immunofluorescence histochemistry. The results showed that: (1) following the unilateral Fluoro-Gold (FG) injections into the ventral posteromedial nucleus (VPM) of the thalamus and the separated parts of the "zone-shaped area", viz, Vpdm, ADO and AVM, many FG-labeled neurons were always found contralaterally in the "zone-shaped area" and ipsilaterally in the Vodm-LRF, respectively; (2) in either the "zone-shaped area" or the Vodm-LRF, a substantial number of the FG retrogradely labeled neurons showed PV-LI. In the Vsup-CL, Vpdm, AVM and ADO, about 57%, 55%, 11% and 4% of the neurons projecting to the VPM of the thalamus showed pV-LI, respectively. Of the total population of PV-LI neurons in the Vsup-CL, Vpdm. AVM and ADO, about 23%, 79%, 53% and 16% were labeled by FG, respectively. Most of these PV/FG double-labeled neurons were medium- to small-sized, round, piriform or irregular in shape. On the other hand, in the Vodm-LRF, approximately 33%, 34% and 50% of the neurons which projected to the Vpdm, AVM and ADO expressed PV-LI, respectively. The percentage of PV/FG double-labeled neurons to the total number of the PV-LI neurons in Vpdm, AVM or ADO were 26%, 17% or 11%, respectively, The present results indicated that PV might play an important role in the transmission of the trigeminal proprioceptive information of the rat from Vndm-LRF to the contralateral VPM of the thalamus through the "zone-shaped area".

THE PROJECTION OF THE CEREBRAL CORTEX TO THE ORAL SUBNUCLEUS OF SPINAL TRIGEMINAL NUCLEUS IN THE CAT——A STUDY WITH THE HRP RETROGRADE TRACING METHOD / 解剖学报

The cortical distribution of thecells of origin of the corticotrigeminal projection to the oral subnucleus of spinal trigeminal nucleus(Vo)was examined with the HRP retrograde tracing method. The results showed that the coronal gyrus was the main site of origin. The anterior part and the posterior part of the gyrus projected to the dorsomedial portion and the ventrolateral portion of Vo respectively. The amount of labelled cells in the anterior part of the gyrus was much larger than those in the posterior. There were also numerous labelled cells in the anterior parts of orbital gyrus and of the lateral zone of anterior sigmoid gyrus. The most anterior ends of these three gyri joined together forming the so-called "presylvian gyrus" where the labelled cells were most concentrated. In addition, the labelled cells were also scattered in the anterior suprasylvian gyrus, posterior sigmoid gyrus, lateral gyrus and anterior ectosylvian gyrus. All labelled cells were located in the fifth layer of the cortex. Their size varied. The results of the present study did not support that there were projections from the temporal and occipital lobes and proreate gyrus to Vo.

ULTRASTRUCTURE OF THE DESCENDING RUBRAL FIBERS IN LAMINA V OF THE CAT TRIGEMINAL SUBNUCLEUS CAUDALIS——HRP LABELING AND DEGENERATION STUDY / 解剖学报

After a injection of kainic acid or WGA-HRP into the red nucleus, the degenerated or HRP labeled terminals in lamina V of the contralateral trigeminal subnucleus caudalis (Vc) were examined electron microscopically. It was found that the degenerated and HRP labeled terminals contained vesicles of spherical or mixed type, and formed symmetrical synapses with medium- or small-sized dendrites. These findings suggested that the descending rubral fibers might be inhibitory in regulating the activity of the neurons, and supposed to be sensory in nature. Thus the red nucleus might play certain role in modulation of the oro-facial somatosensory transmission (including pain) in lamina V of Vc, besides the rubrospinal influence on the involuntary motor functions of the spinal anterior horn. The technique for tracing neural connections with electron microscope was discussed as well.

THE DISTRIBUTION OF LARGE GRANULAR VESICLES IN SUBSTANCE P AXON TERMINALS AND THEIR SYNAPTIC RELATIONS IN THE TRIGEMINAL SUBNUCLEUS CAUDALIS / 解剖学报

The ultrastructural localization of substance P (SP) immunoreactivity, especially the morphology, number and distribution of positive large granular vesicles (LGV) in SP axon terminals of the trigeminal subnucleus caudalis of the rat were studied by electron microscopic immunocytochemistry. This study revealed that SP immunoreactivity was mostly located in axon terminals and unmyelinated fibers. SP axon terminals contained both clear round vesicles and LGV. SP immunoreactivity was found in LGV, and on the surface of clear round vesicles and outer membrane of mitochondria. Positive LGV were spherical or oval in shape (60～120nm in diameter). The number of LGv was mostly 2～3 in a SP axon terminal. LGV often apposed to the axolemma or scattered in the centre of terminal. LGV were far from the presynaptic sites of the SP terminals which formed synapses. The number of LGV closed to the terminal membrane was significantly (P

THE DISTRIBUTION OF NOS-POSITIVE NEURONS IN THE PROJECTING PATHWAY TO THE SUBNUCLEUS RETICULARIS DORSALIS IN THE RAT / 解剖学报

Objective To observe the distribtuion of NOS positive neurons in the projecting pathway to the subnucleus reticularis dorsalis(SRD) in the rat. Methods We used a double staining technique combined retrograde tract tracer and NADPH d histochemistry. Results FG/NOS double labeled neurons were found in the laminae Ⅰ,Ⅹ of spinal cord,dorsal raphe nucleus(DR),linear raphe nucleus(LR),and raphe obscurus nucleus(RO).In the periaqueductal gray(PAG),there were many FG labeled or NOS labeled neurons,but no FG/NOS double labeled neurons were found.Conclusion\ NO might play a role in the pathway of afferent projections of the SRD.\;[

MORPHOLOGICAL STUDIES OF LARGE DENSE CORE VESICLE NONSYNAPTIC EXOCYTOSIS AND MEMBRANE RECYCLING IN THE TRIGEMINAL SUBNUCLEUS CAUDALIS / 解剖学报

Large dense core vesicle in the trigeminal subnucleus caudalis of the rat has been observed electron microscopically. It is fixed in glutaraldehyde-osmium tetroxide following removal of the skin of the vibrissae areas. The findings of the present study are: 1.Morphological evidence for exocytosis of large dense core vesicle from non-synaptic sites of the axonal terminal has been presented.2. The large coated vesicles equipped with central densities derived from the invagination of the plasma membrane. These observations suggest that membrane recycling occur at location in the terminal via these coated vesicles.3.Some large dense core vesicles may also form the tubular structures which may represent smooth endoplasmic reticulum containing dense material. This study supports the hypothesis that release of the transmitter of the great dense core vesicles occur at nonsynaptic sites by exocytosis.