Primary afferent projections from the upper respiratory tract in the muskrat.

The central projections of the ethmoidal, glossopharyngeal, and superior laryngeal nerves were determined in the muskrat by use of the transganglionic transport of a mixture of horseradish peroxidase (HRP) and wheat germ agglutinin (WGA)-HRP. The ethmoidal nerve projected to discrete areas in all subdivisions of the ipsilateral trigeminal sensory complex. Reaction product was focused in ventromedial portions of the principal nucleus, subnucleus oralis, and subnucleus interpolaris. The subnucleus oralis also contained sparse reaction product in its dorsomedial part. Projections were dense to ventrolateral parts of laminae I and II of the rostral medullary dorsal horn, with sparser projections to lamina V. Label in laminae I and V extended into the cervical dorsal horn. A few labeled fibers were followed to the contralateral dorsal horn. The interstitial neuropil of the ventral paratrigeminal nucleus was densely labeled. Extratrigeminal primary afferent projections in ethmoidal nerve cases involved the K?lliker-Fuse nucleus and ventrolateral part of the parabrachial nucleus, the reticular formation surrounding the rostral ambiguous complex, and the dorsal reticular formation of the closed medulla. Retrograde labeling in the brain was observed in only the mesencephalic trigeminal nucleus in these cases. The cervical trunk of the glossopharyngeal and superior laryngeal nerves also projected to the trigeminal sensory complex, but almost exclusively to its caudal parts. These nerves terminated in the dorsal and ventral paratrigeminal nuclei as well as lamina I of the medullary and cervical dorsal horns. Lamina V received sparse projections. The glossopharyngeal and superior laryngeal nerves projected to the ipsilateral solitary complex at all levels extending from the caudal facial nucleus to the cervical spinal cord. At the level of the obex, these nerves projected densely to ipsilateral areas ventral and ventromedial to the solitary tract. Additional ipsilateral projections were observed along the dorsolateral border of the solitary complex. Near the obex and caudally, the commissural area was labeled bilaterally. Labeled fibers from the solitary tract projected into the caudal reticular formation bilaterally, especially when the cervical trunk of the glossopharyngeal nerve received tracer. Labeled fibers descending further in the solitary tract gradually shifted toward the base of the cervical dorsal horn. The labeled fibers left the solitary tract and entered the spinal trigeminal tract at these levels. Retrogradely labeled cells were observed in the ambiguous complex, especially rostrally, and in the rostral dorsal vagal nucleus after application of HRP and WGA-HRP to either the glossopharyngeal or superior laryngeal nerves. In glossopharyngeal nerve cases, retrogradely labeled neurons also were seen in the inferior salivatory nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)     

三叉旁核内含P物质的三叉神经初级传入终末的电镜研究

作用辣根过氧化物酶跨节追踪结合包埋后胶体金免疫电镜技术方法，对三叉旁核内含Ｐ物质的三叉神经初级传入终末形态和突触构筑进行了观察，这类终末大多较细，主要与树突和树突棘构成突触联系，另外，作还区分了三叉旁核内不含Ｐ物质的三叉神经初级传入终末以及含Ｐ物质的非三叉神经终末，上述结果提示三叉旁核可能感受与感合经不同类型终末传入的痛与非痛性感觉信息。     

Distinct patterns of neuronal inputs and outputs of the juxtaparaventricular and suprafornical regions of the lateral hypothalamic area in the male rat

We have analyzed at high resolution the neuroanatomical connections of the juxtaparaventricular region of the lateral hypothalamic area (LHAjp); as a control and in comparison to this, we also performed a preliminary analysis of a nearby LHA region that is dorsal to the fornix, namely the LHA suprafornical region (LHAs). The connections of these LHA regions were revealed with a coinjection tract-tracing technique involving a retrograde (cholera toxin B subunit) and anterograde (Phaseolus vulgaris leucoagglutinin) tracer. The LHAjp and LHAs together connect with almost every major division of the cerebrum and cerebrospinal trunk, but their connection profiles are markedly different and distinct. In simple terms, the connections of the LHAjp indicate a possible primary role in the modulation of defensive behavior; for the LHAs, a role in the modulation of ingestive behavior is suggested. However, the relation of the LHAjp and LHAs to potential modulation of these behaviors, as indicated by their neuroanatomical connections, appears to be highly integrative as it includes each of the major functional divisions of the nervous system that together determine behavior, i.e., cognitive, state, sensory, and motor. Furthermore, although a primary role is indicated for each region with respect to a particular mode of behavior, intermode modulation of behavior is also indicated. In summary, the extrinsic connections of the LHAjp and LHAs (so far as we have described them) suggest that these regions have a profoundly integrative role in which they may participate in the orchestrated modulation of elaborate behavioral repertoires.     

Role of neurokinin receptors and ionic mechanisms within the respiratory network of the lamprey

We have suggested that in the lamprey, a medullary region called the paratrigeminal respiratory group (pTRG), is essential for respiratory rhythm generation and could correspond to the pre-Bötzinger complex (pre-BötC), the hypothesized kernel of the inspiratory rhythm-generating network in mammals. The present study was performed on in vitro brainstem preparations of adult lampreys to investigate whether some functional characteristics of the respiratory network are retained throughout evolution and to get further insights into the recent debated hypotheses on respiratory rhythmogenesis in mammals, such as for instance the “group-pacemaker” hypothesis. Thus, we tried to ascertain the presence and role of neurokinins (NKs) and burst-generating ion currents, such as the persistent Na⁺ current (I_NaP) and the Ca²⁺-activated non-specific cation current (I_CAN), described in the pre-Bötzinger complex. Respiratory activity was monitored as vagal motor output. Substance P (SP) as well as NK1, NK2 and NK3 receptor agonists (400–800 nM) applied to the bath induced marked increases in respiratory frequency. Microinjections (0.5–1 nl) of SP as well as the other NK receptor agonists (1 μM) into the pTRG increased the frequency and amplitude of vagal bursts. Riluzole (RIL) and flufenamic acid (FFA) were used to block I_NaP and I_CAN, respectively. Bath application of either RIL or FFA (20–50 μM) depressed, but did not suppress respiratory activity. Coapplication of RIL and FFA at 50 μM abolished the respiratory rhythm that, however, was restarted by SP microinjected into the pTRG. The results show that NKs may have a modulatory role in the lamprey respiratory network through an action on the pTRG and that I_NaP and I_CAN may contribute to vagal burst generation. We suggest that the “group-pacemaker” hypothesis is tenable for the lamprey respiratory rhythm generation since respiratory activity is abolished by blocking both I_NaP and I_CAN, but is restored by enhancing network excitability.     

Raeder's syndrome. A case with an unusual localization

We describe a patient with a Raeder's paratrigeminal neuralgia consisting of left-sided frontal and orbital pain, Homer syndrome (including anhydrosis of the forehead), and sensory loss in the territory of the first division of the trigeminal nerve. The involvement of the ophthalmic nerve is not consistent with the usual localization of this syndrome to the pericarotid sympathetic plexus. Oculosympathetic and sympathetic fibers supplying the sweat glands of the forehead join the ophthalmic nerve in the cavernous plexus localized in the cavernous sinus. Therefore, this seems to be the most likely site of the lesion when the ophthalmic nerve is involved.     

Relative 2-deoxyglucose uptake of the paratrigeminal nucleus increases during hibernation

The paratrigeminal nucleus, a little-studied cell group of the medulla, is the only structure of the brain to significantly increase its relative [¹⁴C]2-deoxyglucose accumulation during hibernation in the ground squirrel. The zone of increased activity on the autoradiographs is continuous between this structure and the marginal zone of the spinal trigeminal nucleus. Because of the known thermoafferent function of the latter structure, a similar function is suggested for the paratrigeminal nucleus.     

Cerebral and Oculorhinal Manifestations of a Limited Form of Wegener's Granulomatosis With c-ANCA—Associated Vasculitis

The authors report on cerebral and oculorhinal manifestations in a patient with a cytoplasmic pattern of antineutrophil cytoplasmic autoantibody (c‐ANCA)—associated vasculitis. Recurrent Tolosa‐Hunt syndrome, cavernous sinus syndrome, Raeder's paratrigeminal neuralgia, and seizures were the major clinical manifestations. Brain MRI showed localized enhancing lesions initially in the cavernous sinus and later in the convexity pachymeninges. The lesions disappeared following 9 months of oral prednisolone (15 mg/day) and cyclophosphamide (100 mg/day) therapy. The presence of c‐ANCA, demonstration of vasculitis, and depositions of immunoglobulin G (IgG) and fibrinogen in the vessel walls of pachymeninges of the patient confirmed an immune‐mediated cause of the vasculitis. Cranial pathology without renal and pulmonary involvement suggests a variant of Wegener's granulomatosis, which is called the “limited” form of Wegener's granulomatosis.     

Spinal and trigeminal dorsal horn projections to the parabrachial nucleus in the rat

We studied afferents to the parabrachial nucleus (PB) from the spinal cord and the spinal trigeminal nucleus pars caudalis (SNVc) in the rat by using the anterograde and retrograde transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). Injections of WGA-HRP into medial PB retrogradely labeled neurons in the promontorium and in lamina I of the dorsal rostral SNVc, while injections into lateral PB and the K?lliker-Fuse nucleus retrogradely labeled neurons in these areas as well as in lamina I throughout the caudal SNVc and spinal dorsal horn. Injections of WGA-HRP into the caudal SNVc and dorsal horn of the spinal cord resulted in terminal labeling in the dorsal, central, and external lateral subnuclei of PB and the K?lliker-Fuse nucleus, all of which are known to receive cardiovascular and respiratory afferent information. Injections of WGA-HRP into the promontorium and dorsal rostral SNVc resulted in terminal labeling in the same PB subnuclei, as well as in the medial and the ventral lateral PB subnuclei, which are sites of relay for gustatory information ascending from the medulla to the forebrain. The spinal and trigeminal projection to PB may mediate the convergence of pain, chemosensory, and temperature sensibilities with gustatory and cardiorespiratory systems in PB.     

Trigeminal primary afferent terminals containing substance P－like immunoreactivity in the paratrigeminal nucleus

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Intracranial internal carotid artery aneurysm as a cause of raeder's paratrigeminal syndrome

A 26-year-old woman was first seen with severe facial pain, partial Horner's syndrome, and restriction of ocular movements on the right side—all features of Raeder's paratrigeminal syndrome. Right carotid angiogram revealed an aneurysm of the internal carotid artery. This is the second reported case of Raeder's syndrome due to an aneurysm of the intracranial portion of the internal carotid artery. The mechanism of facial pain and sympathetic involvement are discussed.