Hypoxia and nicotine effects on Pituitary adenylate cyclase activating polypeptide (PACAP) and its receptor 1 (PAC1) in the developing piglet brainstem

Pituitary adenylate cyclase activating polypeptide (PACAP) and its cognate receptor 1 (PAC1), have been implicated in the pathophysiology of the Sudden Infant Death Syndrome (SIDS). Two main risk factors for SIDS are prone sleeping and cigarette smoke exposure. Using piglet models of these risk factors, intermittent hypercapnic hypoxia (IHH-mimicking rebreathing in prone position) and nicotine (main reinforcing element of cigarettes), this study aimed to determine their effects on PACAP and PAC1 protein expression in the medulla. IHH was delivered for 1 (n = 7), 2 (n = 6), 3 (n = 6) and 4 (n = 7) days prior to euthanasia at 13–14 days of age, while nicotine (n = 7) was continuous for the first 14 days of life. An additional group of combined nicotine and 1 day IHH (1DIHH) was studied to determine the combined effects of the risk factors. Changes in expression were seen after the acute 1DIHH exposure (none after repeated daily exposures) and included a decrease in PACAP in the dorsal motor nucleus of vagus (DMNV; p = 0.024), nucleus of the solitary tract (NTS; p = 0.024) and the gracile nucleus (GRAC; p = 0.001), and a decrease in PAC1 in the NTS (p = 0.01). No PACAP change was noted in the nicotine-exposed piglets, however, a decrease in PAC1 was found in the DMNV (p = 0.02). IHH exposure in piglets with pre-exposure to nicotine led to a significant decrease in PACAP in the Grac (p = 0.04) but had no effect on PAC1. These findings show for the first time, the vulnerability of PACAP in the brainstem during early development to an acute hypercapnic hypoxic exposure and that those effects are greater than from nicotine exposure.     

Stimulation of the chewing area of the cerebral cortex induces inhibitory effects upon swallowing in sheep

Mastication and swallowing are two tightly integrated components of food intake behavior. We investigated the effects of stimulating the chewing area of the fronto-orbital cortex (CCx) on some muscles and medullary interneurons (Ins) or motoneurons (Mns) active during swallowing. For the purpose of comparison, the lingual nerve (LN) was also stimulated during the experiments. Electromyography (EMG) and extracellular neuronal recording were used, and swallowing was reflexly induced (RIS) by stimulation of the superior laryngeal nerve (SLN). RIS was almost totally abolished during long-lasting repetitive stimulation of CCx or LN, and was strongly facilitated after stimulation cessation. Short-duration stimulation (one or a few pulses) of both the CCx and LN also inhibited triggering of deglutition when delivered just before the onset of RIS. This inhibition appeared as a delay or total suppression of the EMG and neuronal swallowing activities. It was obvious at the level of the muscles, the hypoglossal Mns and the premotoneurons (PMns; Ins of the ventral medulla near the nucleus ambiguus), as well as at the level of the Ins of the dorsal medulla (within or around the solitary tract nucleus) which are assumed to be the core of the ‘central pattern generator' (CPG) for swallowing. In addition to the ‘chewing-related inhibition', many ventral Ins exhibited a short latency synaptic activation after CCx and/or LN stimulation. Therefore, these Ins may play a pivotal role for reflex or cortical fast control of tongue (and jaw) muscles, and for coordinating their contractions in the context of mastication–deglutition interactions.     

帕金森病发病危险因素的研究

目的 探讨帕金森病发病的危险因素。方法 利用病例对照研究方法对１００例ＰＤ患者和１００例年龄及性别相匹配的对照组进行分析,并对７２例ＰＤ和６６例对照者的载脂蛋白Ｅ基因型进行检测。结果 发现引起ＰＤ发病的危险因素包括不良环境暴露,幼年期的居住地,脑外伤,阳性家族史及农业劳动等;同时发现ａｐｏＥ等位基因频率在ＰＤ和本研究的对照组间分布无显著性差异。     

Primary clear cell sarcoma of soft tissue in the posterior cervical spine invading the medulla oblongata: A case report

BACKGROUNDClear cell sarcoma (CCS) is a rare and highly malignant soft tissue tumor, usually occurring in the deep soft tissues of the distal tendons and aponeurosis of the extremities, especially the feet and knees. CCS originating in the head and neck is extremely rare. The clinical manifestations of CCS in the head and neck are not typical, and the imaging manifestations have certain characteristics, but the diagnosis still depends on pathological examination and genetic testing.CASE SUMMARYA 33-year-old male patient had paroxysmal headache for more than 4 years, accompanied by nausea and vomiting, which could be relieved after rest. Computed tomography angiography showed a left paraspinal soft tissue mass. Contrast-enhanced imaging showed obvious uneven enhancement with adjacent bone lytic destruction. Magnetic resonance imaging examination showed isosignal on T₁-weighted images, slightly high signal on T₂-weighted images (T₂WI), high signal on Tirm fat suppression sequence, significantly high signal on diffusion weighted imaging, and obvious and uneven enhancement. The lesion invaded the anterior medulla oblongata through the left atlantoaxial foramen and compressed the cervical spinal cord on T₂WI. Primary CCS of soft tissue was diagnosed by pathology and genetic examination.CONCLUSIONCCS should be considered in the differential diagnosis of soft tissue tumors of the head and neck, and their diagnosis depends on pathological examination and genetic testing.     

基于RBF和PSO的双喉道气动矢量喷管优化设计

目的 探讨3-巯基丙酮酸转硫酶(3-mercaptopyruvate sulfurtransferase,3MST)在正常新生大鼠延髓的表达及宫内香烟烟雾暴露对其表达的影响.方法 SD孕鼠随机分为正常对照组和香烟烟雾暴露组(n=8),与孕鼠相对应的新生(1 d)大鼠为本研究的实验对象.采用RT-PCR和Western blot法,分别观察正常新生大鼠延髓组织中3MST mRNA和蛋白的表达情况及宫内香烟烟雾暴露对其表达的影响;采用免疫组织化学法观察正常新生大鼠延髓呼吸相关核团神经元3MST的表达和分布情况及宫内香烟烟雾暴露对其表达的影响.结果 正常对照组新生大鼠延髓组织中有3 MST mRNA和蛋白的表达;香烟烟雾暴露组新生大鼠延髓组织中3MST mRNA和蛋白的表达水平显著增加(P＜0.05).3MST在正常对照组新生大鼠前包钦格复合体(pre-B(o)tC)、舌下神经核(12N)、疑核(Amb)、面神经核(FN)和孤束核(NTS)神经元中有弱表达.与对照组比较,香烟烟雾暴露组新生大鼠preB(o)tC、12N、Amb和FN神经元中3MST免疫阳性产物平均光密度值增加(P＜0.05);NTS神经元中3MST免疫阳性产物平均光密度值无明显变化(P＞0.05).结论 3MST存在于正常新生大鼠延髓呼吸相关核团神经元;宫内香烟烟雾暴露可上调延髓3MST的表达,提示3MST-硫化氢(H2S)途径可能参与宫内香烟烟雾暴露致新生大鼠延髓呼吸中枢损伤保护过程.     

Nucleus ambiguus and bulbospinal ventral respiratory group neurons in the neonatal rat

The in vitro brainstem-spinal cord preparation of the neonatal rat is an important model system for studies of the respiratory control system, yet there have not been studies to anatomically characterize respiratory neuron populations in the neonate. Fluorescent retrograde tracers were used to identify bulbospinal neurons of the ventral respiratory group and motoneurons of nucleus ambiguus in neonatal rats. Fluoro-Gold injections into the C₄ ventral horn labeled bulbospinal neurons within a densely packed column within the ventrolateral intermediate reticular nucleus from the level of the pyramidal decussation to the facial nucleus. This cell column corresponded closely to the location of the ventral respiratory group of the adult rat. In particular, neurons were labeled in regions corresponding to the rostral ventral respiratory group and the Bötzinger complex. Unlike adult rats, the preBötzinger complex also contained many bulbospinal neurons. Fluoro-Gold–labeled neurons were also located in the medial reticular nuclei, raphe pallidus, and obscurus and spinal vestibular nucleus. As in adult rats, bulbospinal ventral respiratory group neurons overlapped with cervical vagal motoneurons in the external formation, and partially with those in the loose formation, but not with those in the semicompact or compact formation of nucleus ambiguus. These results indicate that the distribution of bulbospinal ventral respiratory group neurons corresponds with that observed in physiological studies of neonatal rats.     

Respiratory-modulated neuronal activities of the rostral medulla which may generate gasping

Different neurophysiological mechanisms have been proposed to generate eupnea and gasping. Gasping is generated by neuronal mechanisms intrinsic to the medulla whereas a ponto-medullary neuronal circuit has been hypothesized to generate eupnea. Hence, neurons in the rostral medullary region which are critical for the neurogenesis of gasping are hypothesized to discharge differently in eupnea and gasping. In a perfused in situ preparation of the juvenile rat, these rostral medullary neuronal activities had inspiratory, expiratory and phase-spanning patterns in eupnea. In gasping, most expiratory and phase-spanning activities ceased, whereas many inspiratory neuronal activities changed to a decrementing pattern as that of the phrenic nerve. A limited proportion of neuronal activities acquired a 'pre-inspiratory' discharge in gasping. These neuronal activities, which were inspiratory or phase-spanning in eupnea, commenced discharge in neural expiration. This discharge peaked at the onset of the gasp and then decremented during neural inspiration. We hypothesize that these 'pre-inspiratory' neuronal activities generate the gasp by intrinsic pacemaker mechanisms.     

Migration of an acupuncture needle into the medulla oblongata

Summary A case of a delayed lesion of the medulla oblongata caused by migration of an acupuncture needle is presented. The patient was a 60-year-old woman who had undergone embedded-type acupuncture needle treatment around 1975. In 1993 she was admitted to our hospital with a 3-week history of progressive motor and sensory disturbance of her right upper extremity. CT demonstrated that one needle had penetrated the medulla oblongata transversely at the level of the foramen magnum. The needle was removed surgically without any complications. This is the first report of an acupuncture needle migrating into the medulla oblongata.     

Expression of metabotropic glutamate receptor 8 in autonomic cell groups of the medulla oblongata of the rat

Metabotropic glutamate receptors (mGluRs) in the medulla oblongata have been suggested to have a functional role in the regulation of cardiovascular baroreflexes. The present study examines the localization of mGluR8 autonomic nuclei of the medulla of the rat. mGluR8 immunoreactivity was observed in the cell bodies and/or processes of the dorsolateral, interstitial, medial, intermediate, ventral, ventrolateral, subpostremal, commissural, parvicellular and gelatinosus subnuclei of the nucleus tractus solitarius (NTS). The intensity of mGluR8 staining was highest in the commissural and interstitial subnuclei at the level of the area postrema. Commissural NTS is involved in regulation of baro-, and chemo-reflexes whereas the interstitial nucleus mediates respiratory reflexes. In the area postrema, diffuse staining was observed in the cell bodies, dendrites and fibers of the dorsal and central regions. In vagal outflow nuclei, mGluR8 immunoreactivity was observed in: (1) the cell bodies and processes of the dorsal motor nucleus of the vagus (DMN) throughout the rostro-caudal extent; and (2) the cell bodies and fibers throughout the rostro-caudal extent of the dorsal and ventral division the nucleus ambiguus (NA). Staining in the ventrolateral medulla was restricted to regions ventral to the nucleus ambiguus and dorsal to the lateral reticulate nucleus. The present study is the first to provide a detailed mapping of mGluR8 within the autonomic nucleii of the medulla and suggests that this subtype may be involved in shaping synaptic transmission in these central nuclei.     

Histological structures in the chemosensitive regions on the ventral surface of the cat's medulla oblongata

Summary The region on the ventral surface of the medulla oblongata (see preceding communication) responding maximally to both electrical and chemical stimulation by inducing an increase of ventilation was marked electrolytically and examined histologically. A characteristic group of large multipolar nerve cells was always found at the spot marked by electrolysis.These cells are located medial to the hypoglossal roots and ventral to the inferior olive which separates them from the respiratory centers. The cells are distributed at a distance of 8–450 m from the ventral surface of the medulla oblongata, the greatest concentration being located at 150–200 m beneath the surface.The possible role of these cells in the central chemical respiratory drive is discussed.Im Rahmen des Programms des Sonderforschungsbereiches 114 (Bionach) der Deutschen Forschungsgemeinschaft.