Revisão de anatomia e correlações clínicas do tronco encefálico, parte i: bulbo / Review of brain anatomy and clinical correlations, part i: medulla

O Tronco encefálico (TE) é uma estrutura singular do sistema nervoso central, pois nele passam tratos sensoriais ascendentes da medula espinal, tratos sensoriais da cabeça e do pescoço, os tratos descendentes motores originados no prosencéfalo (divisão mais rostral do encéfalo), e as vias ligadas aos centros de movimento dos olhos. Contém ainda os núcleos dos nervos cranianos e está envolvido na regulação do nível de consciência através de projeções ao prosencéfalo oriundas da formação reticular. Todas essas estruturas coexistem em um espaço muito exíguo, o que faz com que o TE seja um local muito sensível às alterações patológicas, sendo que os pacientes apresentam muitos sinais neurológicos mesmo com lesões muito pequenas nesse local. Compreender a anatomia interna do TE é essencial para o diagnóstico neurológico e a prática da medicina clínica. Outros profissionais da saúde também se beneficiam desse conhecimento para melhor manejo dos seus pacientes neurológicos. Essa revisão apresenta detalhes da anatomia macroscópica e microscópica do bulbo, bem como seus correlatos clínicos frente às lesões mais comuns dessa divisão particular do TE, conhecidas como síndromes bulbares.

The brainstem is a unique structure in the central nervous system, since it gives way to ascending sensory tracts from the spinal cord, sensory tracts from the head and neck, motor descending tracts originating from the forebrain, and the pathways connected to the eye movement centers. It also contains the cranial nerve nuclei and is involved in the regulation of consciousness levels through projections to the forebrain originating in the reticular formation. All these structures coexist in a very small space, which makes the brainstem very sensitive to pathological changes, with patients presenting several neurological symptoms even with very small brainstem lesions. Understanding the internal anatomy of the brainstem is essential for neurological diagnosis and the practice of clinical medicine. Other health professionals also benefit from this knowledge to better manage their neurological patients. This review presents detailed information on the macroscopic and microscopic anatomy of the medulla, as well as its clinical correlates in the face of the most common lesions of this particular division of the brainstem, known as medullary syndromes.

Rhizoglyphus echinopus (Acari: Acaridae) associated with Atta sexdens (Insecta: Formicidae) / Rhizoglyphus echinopus (Acari: Acaridae) associado a Atta sexdens (Insecta: Formicidae)

Four deutonymphs of bulb mites (hypopus) from Rhizoglyphus echinopus (Fumouze & Robin) (Acari: Acaridae) were found attached to the head of Atta sexdens in Rio de Janeiro, Brazil. This mite species is commonly associated with ornamental plants and trees with bulbs, corms and tubers. The results of this study provided an insight into the phoretic relationship between mites and ants, indicating the role of the latter in the dispersion of the first. Despite the abundant and diverse mite fauna existing in ants, little is known about their diversity, biology, ecology and the nature of their associations.(AU)

Quatro deutoninfas de ácaros do bulbo (hipopus) da espécie Rhizoglyphus echinopus (Fumouze & Robin) (Acari: Acaridae) foram encontradas fixadas na cabeça de formigas da espécie Atta sexdens no Rio de Janeiro, Brasil. Essa espécie de ácaro está comumente associada a plantas ornamentais e plantas com bulbos e tubérculos. Os resultados desse estudo fornecem uma visão sobre a relação forética entre ácaros e formigas, indicando o papel destas últimas na dispersão dos primeiros. Apesar da abundância e da fauna diversa do ácaro em formigas, pouco se sabe sobre a diversidade, a biologia, a ecologia e a natureza dessa associação.(AU)

Environmental Enrichment Promotes Antioxidant Effect in the Ventrolateral Medulla and Kidney of Renovascular Hypertensive Rats / O Enriquecimento Ambiental Promove Efeito Antioxidante no Bulbo Ventrolateral e Rins de Roedores com Hipertensão Renovascular

Abstract Background: Arterial hypertension is a precursor to the development of heart and renal failure, furthermore is associated with elevated oxidative markers. Environmental enrichment of rodents increases performance in memory tasks, also appears to exert an antioxidant effect in the hippocampus of normotensive rats. Objectives: Evaluate the effect of environmental enrichment on oxidative stress in the ventrolateral medulla, heart, and kidneys of renovascular hypertensive rats. Methods: Forty male Fischer rats (6 weeks old) were divided into four groups: normotensive standard condition (Sham-St), normotensive enriched environment (Sham-EE), hypertensive standard condition (2K1C-St), and hypertensive enriched environment (2K1C-EE). Animals were kept in enriched or standard cages for four weeks after all animals were euthanized. The level of significance was at p < 0.05. Results: 2K1C-St group presented higher mean arterial pressure (mmHg) 147.0 (122.0; 187.0) compared to Sham-St 101.0 (94.0; 109.0) and Sham-EE 106.0 (90.8; 117.8). Ventrolateral medulla from 2K1C-EE had higher superoxide dismutase (SOD) (49.1 ± 7.9 U/mg ptn) and catalase activity (0.8 ± 0.4 U/mg ptn) compared to SOD (24.1 ± 9.8 U/mg ptn) and catalase activity (0.3 ± 0.1 U/mg ptn) in 2K1C-St. 2K1C-EE presented lower lipid oxidation (0.39 ± 0.06 nmol/mg ptn) than 2K1C-St (0.53 ± 0.22 nmol/mg ptn) in ventrolateral medulla. Furthermore, the kidneys of 2K1C-EE (11.9 ± 2.3 U/mg ptn) animals presented higher superoxide-dismutase activity than those of 2K1C-St animals (9.1 ± 2.3 U/mg ptn). Conclusion: Environmental enrichment induced an antioxidant effect in the ventrolateral medulla and kidneys that contributes to reducing oxidative damage among hypertensive rats.

Resumo Fundamento: A hipertensão arterial é um precursor para o desenvolvimento da insuficiência cardíaca e renal e, além disso, está associada com o aumento dos marcadores oxidativos. O enriquecimento ambiental dos roedores melhora o desempenho em tarefas de memória, e também parece ter um efeito antioxidante sobre o hipocampo dos ratos normotensos. Objetivos: Avaliar o efeito do enriquecimento ambiental sobre o estresse oxidativo no bulbo ventrolateral, coração, e rins de ratos com hipertensão renovascular. Métodos: Quarenta ratos machos, tipo Fischer (6 semanas de idade), foram divididos em quatro grupos: normotensos em condições padrão (Sham-CP), normotensos em ambiente enriquecido (Sham-AE), hipertensos em condições padrão (2R1C-CP), e hipertensos em ambiente enriquecido (2R1C-AE). Os animais foram mantidos em gaiolas enriquecidas ou padrão durante quatro semanas e, por fim, todos os animais foram eutanasiados. O nível de significância foi p < 0,05. Resultados: O grupo 2R1C-CP apresentou pressão arterial média maior (mmHg) 147,0 (122,0; 187,0) quando comparado com os grupos Sham-CP 101,0 (94,0; 109,0) e Sham-AE 106,0 (90,8; 117,8). Observou-se maior atividade das enzimas superóxido dismutase (SOD) (49,1 ± 7,9 U/mg ptn) e da catalase (0,8 ± 0,4 U/mg ptn) no bulbo ventrolateral do grupo 2R1C-AE, em relação à atividade da SOD (24,1 ± 9,8 U/mg ptn) e da catalase (0,3 ± 0,1 U/mg ptn) no grupo 2R1C-CP. No grupo 2R1C-AE, a oxidação lipídica no bulbo ventrolateral foi menor (0,39 ± 0,06 nmol/mg ptn) quando comparado com o grupo 2R1C-CP (0,53 ± 0,22 nmol/mg ptn). Ademais, foi observada maior atividade das enzimas superóxido dismutase nos rins dos animais 2R1C-AE (11,9 ± 2,3 U/mg ptn) em relação aos animais 2R1C-CP (9,1 ± 2,3 U/mg ptn). Conclusão: O enriquecimento ambiental provocou efeito antioxidante no bulbo ventrolateral e nos rins, o que contribuiu para a redução do dano oxidante nos ratos hipertensos.

The effect of single-bulb garlic oil extract toward the hematology and histopathology of the liver and kidney in mice

Single garlic has been used as a traditional medicine for hypercholesterolemia and increasing stamina. The aim of this research was to analyze the effect of single-bulb garlic oil (SGO) extract toward hematology and histopathology liver and kidney in mice. Male mice (strain Balb-C, 12 weeks old, weight of 28±3 g) was treated by SGO for 28 days (once per days) with various doses K- (Normal); K+ (SGO 0.0 mg/kg BW); T1 (SGO 6.25 mg/kg BW); T2 (SGO 12.5 mg/kg BW); T3 (SGO 25.0 mg/kg BW); T4 (SGO 50.0 mg/kg BW). The end of the treated mice was sacrificed. Blood was collected to analyze hematology. Liver and kidney were collected then made microanatomy slide with Hematoxylin-Eosin staining. Parameters of hematology are the levels of hemoglobin, hematocrit, number of erythrocytes, and number of leukocytes. Histopathology of liver and kidney determine by cell necrosis. The result of the research showed that SGO increased the number of erythrocytes and leucocytes but there is no effect on the levels of hemoglobin and hematocrit. Histopathology on liver and kidney showed there is no effect in necrosis. The conclusion is the single-bulb garlic oil extract safe if consumed continuously

Síndrome de Opalski, una variante del síndrome de Wallenberg: reporte de caso y revisión de la literatura / Opalski Syndrome, a variant of Wallenberg Syndrome: Case report and literature review

RESUMEN Se presenta un caso local de la variante de Opalski, del síndrome medular lateral (síndrome de Wallenberg) y se hace una revisión de la literatura sobre los síntomas de este cuadro clínico, así como las posibles razones que explican esta modificación en la expresión clínica. La variante de Opalski fue descrita en 1948, ochenta y nueve años después de la descripción original del síndrome por Adolf Wallenberg, su principal característica es la presencia de hemiparesia o hemiplejía del cuerpo del mismo lado de la lesión del bulbo raquídeo. La etiología es vascular en la mayoría de casos, por obstrucción de la arteria cerebelosa postero-inferior o de los ostium de vasos penetrantes que se originan en la arteria. No hay estudios que reporten la incidencia exacta de este cuadro clínico a nivel mundial, sin embargo, su presentación no es tan infrecuente. Lo más interesante al analizar cada caso, es que los hallazgos semiológicos son una muestra de la profunda organización del sistema nervioso.

SUMMARY A clinical case of the Opalski variant of the lateral medullary syndrome (Wallenberg's syndrome) is presented and a literature review about the symptoms of this clinical picture is done, as well as the possible reasons explaining this modification in the clinical expression. The Opalski variant was described in 1948, eighty-nine years after the original description of the syndrome by Adolf Wallenberg, its main feature is the presence of hemiparesis or hemiplegia of the ipsilateral side of the injury in the medulla oblongata. In most cases the etiology is vascular when the postero-inferior cerebellar artery is occluded or there is an obstruction of the ostium of penetrating vessels originating in the artery. There are no studies that accurately report the worldwide incidence of this clinical variant, however, its presentation is not uncommon. The most interesting discovery of each case is that semiological findings are a good example of the profound organization of the nervous system.

Plasmocitoma extramedular em bulbo peniano de cão: relato de caso / Extramedullary plasmacytoma in the penile bulb of a dog: case report

O objetivo deste relato de caso é descrever a ocorrência de plasmocitoma em bulbo peniano de um cão, classificado como uma doença extramedular não cutânea de localização rara e casuística inédita. Um cão, sem raça definida, com sete anos de idade e pesando 15kg, não castrado, apresentou histórico clínico de anorexia, vômitos, anúria e constipação. Ao exame específico da genitália externa, foi encontrada uma massa em bulbo peniano durante a inspeção do prepúcio, aderida à pele e encapsulada, extremamente firme e arredondada, medindo cerca de 6cm de diâmetro. Por meio da ultrassonografia dessa estrutura, foi observado aumento do volume regional com ecotextura heterogênea e ecogenicidade mista, além de neovascularização tecidual ao Doppler colorido. Foi realizada biópsia da massa, sendo verificada a presença de neoplasia de células redondas. A caracterização do tumor foi realizada pela imuno-histoquímica, e as células neoplásicas foram imunoexpressas para CD79a e MUM1, indicando o diagnóstico de plasmocitoma extramedular. Embora os tumores penianos em cães sejam os predominantemente venéreos transmissíveis (TVT), e os plasmocitomas sejam neoplasias raras nessa localização, este relato de caso fornece com ineditismo a ocorrência de plasmocitoma extramedular em bulbo peniano de cão, condição ainda não descrita em veterinária.

Non-cutaneous extramedullary plasmacytomas are relatively rare in dogs, affecting mainly the oral cavity and bowel loops. The involvement of the penile bulb has not been described, a fact of great importance for obstetric and veterinary oncology. The aim of this case report is to describe the occurrence of plasmacytoma in a dog's penile bulb, classified as a non-cutaneous extramedullary disease of rare location and unpublished casuistry. A non castrated dog of undefined breed, with seven years of age and weighing 15kg, presented clinical history of anorexia, vomiting, anuria and constipation. By specific examination of the external genitalia, a penile bulb mass was found in the preputial inspection, which was adhered to the encapsulated skin, extremely firm and rounded, measuring approximately 6 cm in diameter. By ultrasound evaluation of the structure in the penile bulb an increase of regional volume with heterogeneous echotexture and mixed echogenicity and tissue neovascularization upon color Doppler was observed. Incisional biopsy of the mass was performed and showed the presence of neoplasia of round cells. The characterization of the tumor was performed by immunohistochemistry and the neoplastic immuno cells were expressed CD79a and MUM1, indicating the diagnosis of extramedullary plasmacytoma. Although the penile tumors in dogs are predominantly transmissible venereal tumors (TVT) and plasmocytomas are rare neoplasms in this location, this case report provides a novel occurrence of extramedullary plasmacytoma in the penile bulb of a dog, a condition not yet described in veterinary.

Tomografia computadorizada do encéfalo do cão: aspectos da normalidade e correlação anatômica / Computed tomography of the dog's brain: normal aspects and anatomical correlation

Obtiveram-se imagens tomográficas sem alterações da cabeça de cães, visando à familiarização com os aspectos normais do encéfalo e correlacionaram-se os achados com a respectiva anatomia da região estudada. Várias estruturas anatômicas foram identificadas, tais como o parênquima dos lobos frontal, parietal, temporal e occipital, a fissura longitudinal, o sistema ventricular, o cerebelo, o bulbo olfatório, o corpo caloso, o diencéfalo, a ponte, a medula oblonga e o sulco quiasmático, de forma direta ou relacionando-as com estruturas vizinhas que auxiliaram na sua identificação.

Normal tomographic images of dog's heads were obtained, aimed to familiarize them with the normal aspects of the brain and correlate these findings with the relevant anatomy of the region studied. Several anatomical structures, such as the parenchyma of the frontal, parietal, temporal and occipital lobes, the longitudinal fissure, the ventricular system, the cerebellum, the olfactory bulb, the corpus callosum, diencephalon, the pons, the medulla oblongata and the chiasmatic sulcus were directly identified or were related to neighboring structures which helped in their identification.

The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms

OBJECTIVE: In the present study, the peripheral mechanism that mediates the pressor effect of angiotensin-(1-7) in the rostral ventrolateral medulla was investigated. METHOD: Angiotensin-(1-7) (25 pmol) was bilaterally microinjected in the rostral ventrolateral medulla near the ventral surface in urethane-anesthetized male Wistar rats that were untreated or treated (intravenously) with effective doses of selective autonomic receptor antagonists (atenolol, prazosin, methyl-atropine, and hexamethonium) or a vasopressin V1 receptor antagonist [d(CH2)5 -Tyr(Me)-AVP] given alone or in combination. RESULTS: Unexpectedly, the pressor response produced by angiotensin-(1-7) (16 ± 2 mmHg, n = 12), which was not associated with significant changes in heart rate, was not significantly altered by peripheral treatment with prazosin, the vasopressin V1 receptor antagonist, hexamethonium or methyl-atropine. Similar results were obtained in experiments that tested the association of prazosin and atenolol; methyl-atropine and the vasopressin V1 antagonist or methyl-atropine and prazosin. Peripheral treatment with the combination of prazosin, atenolol and the vasopressin V1 antagonist abolished the pressor effect of glutamate; however, this treatment produced only a small decrease in the pressor effect of angiotensin-(1-7) at the rostral ventrolateral medulla. The combination of hexamethonium with the vasopressin V1 receptor antagonist or the combination of prazosin, atenolol, the vasopressin V1 receptor antagonist and methyl-atropine was effective in blocking the effect of angiotensin-(1-7) at the rostral ventrolateral medulla. CONCLUSION: These results indicate that angiotensin-(1-7) triggers a complex pressor response at the rostral ventrolateral medulla that involves an increase in sympathetic tonus, release of vasopressin and possibly the inhibition of a vasodilatory mechanism.

Ultrastructural transneuronal degeneration study of axonal elements within the paratrigeminal nucleus in sinoaortic deafferented rats / Estudo ultraestrutural de degeneração transneuronal dos elementos axonais do núcleo paratrigeminal de ratos com desnervação sino-aórtica

Objective: Morphological study that searched to authenticate the presence of sinoaortic baroreceptor inputs within the dorsolateral medullary nucleus under electron microscopy analysis. Methods: After a 5-day survival period, 9 baroreceptor-denervated rats deeply anaesthetized with equithesin were transcardially perfused and their brains were histologically processed. Results: The neuronal cytoarchitecture of the paratrigeminal nucleus comprehends afferent projections from other nuclei that have a distributive character regarding visceral and nociceptive functions in the cardiovascular reflex integration response. Conclusion: The medial portion of the nucleus receives afferent projections of the rostral ventrolateral medulla, as shown by retrograde neurotracing studies. The present results show that the medial extent of the paratrigeminal nucleus contains degenerated axoplasmic cellular components in sinoaortic deafferented rats. The number of degenerated axonal fibers was also larger in this area of the nucleus.

Objetivo: Estudo morfológico que buscou verificar, por meio de microscopia eletrônica, a presença de aferências de receptores sino-aórticos em núcleo localizado na região dorso-lateral bulbar. Métodos: Após 5 dias de sobrevida, 9 ratos com desnervação sinoaórtica anestesiados com equitesina foram submetidos à perfusão transcardíaca, e o encéfalo de cada um deles foi processado histologicamente. Resultados: A citoarquitetura neuronal do núcleo paratrigeminal compreende projeções aferentes de outros núcleos que apresentam uma característica distributiva em relação às funções viscerais e nociceptivas na integração do reflexo cardiovascular. Conclusão: A porção medial do núcleo recebe projeções aferentes da região rostro-ventrolateral do troncoencefálico, confirmadas por meio de estudos com rastreadores neuronais. Os resultados indicam que a região medial do núcleo paratrigeminal contém o maior número de fibras axonais degeneradas.

Malnutrition affects the pressor response to microinjection of L-glutamate into the RVLM of awake rats

Post-weaning protein malnutrition is often related to the development of cardiovascular and metabolic diseases in humans, as well to changed content of neurotransmitters in the central nervous system under experimental conditions. The rostral ventrolateral medulla (RVLM) is a bulbar region that contains sympathetic premotor neurons; the excitatory amino acid L-glutamate seems to be the main neurotransmitter at this level. The aim of the present study was to evaluate the possible change in the L-glutamate sensitivity of the RVLM neurons of malnourished animals. Male Fischer rats were divided into two groups: control (n = 15) and malnourished (n = 19). Four days before the experiments, guide cannulas were implanted bilaterally in direction of the RVLM for microinjection of L-glutamate. Twenty-four hours before the experiments, the femoral artery was cannulated for cardiovascular recordings. The results showed that the baseline heart rate increased in malnourished compared to control animals (412.18 ± 16.03 bpm vs. 370.74 ± 9.59 bpm, respectively). Malnourished animals presented a dissimilar concentration-dependent pressor response curve to L-glutamate and an attenuated baroreflex gain. Our results suggest that post-weaning protein restriction affects glutamatergic neurotransmission of the baroreflex at the RVLM level.

Angiotensin-II-induced reactive oxygen species along the SFO-PVN-RVLM pathway: implications in neurogenic hypertension

Neurogenic hypertension has been the subject of extensive research worldwide. This review is based on the premise that some forms of neurogenic hypertension are caused in part by the formation of angiotensin-II (Ang-II)-induced reactive oxygen species along the subfornical organ-paraventricular nucleus of the hypothalamus-rostral ventrolateral medulla pathway (SFO-PVN-RVLM pathway). We will discuss the recent contribution of our laboratory and others regarding the mechanisms by which neurons in the SFO (an important circumventricular organ) are activated by Ang-II, how the SFO communicates with two other important areas involved in sympathetic activity regulation (PVN and RVLM) and how Ang-II-induced reactive oxygen species participate along the SFO-PVN-RVLM pathway in the pathogenesis of neurogenic hypertension.

Central chemoreceptors and neural mechanisms of cardiorespiratory control

The arterial partial pressure (P CO2) of carbon dioxide is virtually constant because of the close match between the metabolic production of this gas and its excretion via breathing. Blood gas homeostasis does not rely solely on changes in lung ventilation, but also to a considerable extent on circulatory adjustments that regulate the transport of CO2 from its sites of production to the lungs. The neural mechanisms that coordinate circulatory and ventilatory changes to achieve blood gas homeostasis are the subject of this review. Emphasis will be placed on the control of sympathetic outflow by central chemoreceptors. High levels of CO2 exert an excitatory effect on sympathetic outflow that is mediated by specialized chemoreceptors such as the neurons located in the retrotrapezoid region. In addition, high CO2 causes an aversive awareness in conscious animals, activating wake-promoting pathways such as the noradrenergic neurons. These neuronal groups, which may also be directly activated by brain acidification, have projections that contribute to the CO2-induced rise in breathing and sympathetic outflow. However, since the level of activity of the retrotrapezoid nucleus is regulated by converging inputs from wake-promoting systems, behavior-specific inputs from higher centers and by chemical drive, the main focus of the present manuscript is to review the contribution of central chemoreceptors to the control of autonomic and respiratory mechanisms.

Involvement of catecholaminergic medullary pathways in cardiovascular responses to acute changes in circulating volume

Water deprivation and hypernatremia are major challenges for water and sodium homeostasis. Cellular integrity requires maintenance of water and sodium concentration within narrow limits. This regulation is obtained through engagement of multiple mechanisms and neural pathways that regulate the volume and composition of the extracellular fluid. The purpose of this short review is to summarize the literature on central neural mechanisms underlying cardiovascular, hormonal and autonomic responses to circulating volume changes, and some of the findings obtained in the last 12 years by our laboratory. We review data on neural pathways that start with afferents in the carotid body that project to medullary relays in the nucleus tractus solitarii and caudal ventrolateral medulla, which in turn project to the median preoptic nucleus in the forebrain. We also review data suggesting that noradrenergic A1 cells in the caudal ventrolateral medulla represent an essential link in neural pathways controlling extracellular fluid volume and renal sodium excretion. Finally, recent data from our laboratory suggest that these structures may also be involved in the beneficial effects of intravenous infusion of hypertonic saline on recovery from hemorrhagic shock.

Nuclear Architecture in the Medulla Oblongata of the Adult African Giant Pouched Rat (Cricetomys gambianus, Waterhouse - 1840) / Arquitectura Nuclear en la Médula Oblonga de la Rata Gigante de Carillos Africana Adulta (Cricetomys gambianus, Waterhouse - 1840)

The architecture of cranial and non-cranial nerve nuclei in the medulla oblongata of the African giant pouched rat was studied by means of light microscopy. Serial sections of the medulla oblongata, in coronal and saggital planes, were stained with the cresyl fast violet and silver stains, respectively. Sections in the saggital plane were used as a guide, while coronal sections were used to identify the nuclei in the rostrocaudal extent of the medulla oblongata. With the obex serving as the landmark, nuclei rostral and caudal to the obex were delineated. Cranial nerve nuclei whose architecture were defined were the motor nucleus of hypoglossal nerve, motor nucleus of vagus nerve, cochlear nucleus, vestibular nucleus and nucleus ambiguus, while non-cranial nerve nuclei identified were the olivary nucleus, solitary tract nucleus, gracile nucleus, cuneate nucleus, spinal nucleus of trigeminal nerve, motor nucleus of corpus trapezoideum, lateral nucleus of reticular formation and gigantocellular nucleus. The olivary nucleus was the most prominent nucleus, while the solitary tract nucleus was faint, and thus, less developed. The rostrocaudal extent of the solitary tract nucleus, olivary nucleus and motor nucleus of hypoglossal nerve were 3.81 mm, 2.36 mm and 3.50 mm in length, respectively. The prominent olivary nucleus, pyramidal tract and vestibular nucleus are indicative of a good motor coordination and balance, while the poorly developed solitary tract nucleus points to less efficient autonomic functions in this rodent. The present study will serve as a lead for future neuro-behavioural studies necessary for an effective domestication and adaptation of the African giant pouched rat.

Se estudió mediante microscopía de luz la arquitectura de los núcleos de los nervios craneales y no craneales en la médula oblonga de la rata gigante de carillos africana. Secciones seriales de la médula oblonga, en los planos coronal y sagital, se tiñeron con violeta de cresil rápida y tinción de plata, respectivamente. Como guías se utilizaron secciones en el plano sagital, mientras que, secciones coronales se utilizaron para identificar los núcleos en la extensión rostrocaudal de la médula oblonga. Fueron delineados, con el óbex que actúa como punto de referencia, los núcleos rostral y caudal a éste. Los núcleos de los nervios craneales cuya arquitectura se definió fueron los núcleos: motor del nervio hipogloso, motor del nervio vago, coclear, vestibulares y ambiguo, mientras que los núcleos de los nervios craneales no identificados fueron: olivar, del tracto solitario, grácil, cuneiforme, espinal del nervio trigémino, motor del cuerpo trapezoide, lateral de la formación reticular y gigantocelular. El núcleo olivar fue el más importante, mientras que el núcleo del tracto solitario fue tenue, y por lo tanto, menos desarrollado. Las longitud rostrocaudal de los núcleos del tracto solitario, olivar y motor del nervio hipogloso fueron 3,81 mm, 2,36 mm y 3,50 mm, respectivamente. El núcleo prominente olivar, el tracto piramidal y el núcleo vestibular fueron indicativos de una buena coordinación motora y equilibrio, mientras que el escaso desarrollo de los puntos del núcleo del tracto solitario indican una menor eficiencia de las funciones autonómicas en este roedor. El presente estudio servirá para conducir futuros estudios sobre el neuro-comportamiento necesario para una efectiva domesticación y adaptación de la rata gigante de carillos africana adulta.

Trasplante de epiplon para isquemia en la medula espinal y oblonga / Omental transplantation for ischemia in the spinal cord and medulla oblongata

Objetivo: ilustrar que el empeoramiento microvascular en la médula espinal y médula oblongada pueden ser mejorados por medio de un transplante de epiplón. Material y método: reportamos a 5 pacientes que recibieron transplante de epiplón sobre la médula espinal dorsal, médula espinal cervical y médula oblongada; debido a mielopatía vascular, neuralgia occipital primaria, atrofia olivopontocerebelosa y esclerosis lateral amiotrófica. Básicamente, la misma técnica quirúrgica fue usada en todos ellos: laparotomía y después, laminectomía. Resultados: cada uno de ellos experimentó mejoría neurológica después del primer día del postoperatorio y este resultado fue mejor durante las primeras semanas después de la cirugía que en los siguientes meses o años. Conclusión: concluimos que neuronas y/o axones en el área isquémica y en penumbra isquémica, pueden mejorar si la circulación es restituida a través del omento, y más tarde, a causa de regeneración neuronal.

Anatomía microneuro-quirúrgica del Foramen de Vicq d'Azyr / Microneurosurgical anatomy of the foramen of Vicq d'Azyr

El foramen de Vicq d'Azyr es una expansión en forma triangular de la fisura mediana anterior en la cara ventral del bulbo, en su porción más rostral, justo por debajo de la unión ponto-bulbar. Múltiples ramas vasculares perforantes lo atraviesan para dar irrigación a los núcleos y tractos pontinos y bilbares del tallo cerebral; además, guarda estrecha relación con la unión vértebro-basilar y demás estructuras circundantes. El conocimiento de la microanatomía vascular de esta región es importante para llevar a cabo múltiples procedimientos microneuro-quirúrgicos a la hora de tratar diferentes patologías que afecten esta zona.

Role of the medulla oblongata in normal and high arterial blood pressure regulation: the contribution of Escola Paulista de Medicina - UNIFESP

Several forms of experimental evidence gathered in the last 37 years have unequivocally established that the medulla oblongata harbors the main neural circuits responsible for generating the vasomotor tone and regulating arterial blood pressure. Our current understanding of this circuitry derives mainly from the studies of Pedro Guertzenstein, a former student who became Professor of Physiology at UNIFESP later, and his colleagues. In this review, we have summarized the main findings as well as our collaboration to a further understanding of the ventrolateral medulla and the control of arterial blood pressure under normal and pathological conditions.

Numerosas formas de evidência experimental obtidas nos últimos 37 anos demonstraram inequivocamente que a medula oblongata contém os principais circuitos responsáveis pela geração e manutenção do tono vasomotor e a regulação da pressão arterial. A visão atual que possuímos destes circuitos deriva em grande parte dos estudos de Pedro Guertzenstein, um estudante e mais tarde Professor de Fisiologia da UNIFESP e seus colaboradores. Nesta revisão nós sumarizamos os seus principais resultados assim como a nossa colaboração para uma melhor compreensão da regulação da pressão arterial em condições normais e patológicas.

Role of the caudal pressor area in the regulation of sympathetic vasomotor tone

It is well known that the ventrolateral medulla contains neurons involved in the tonic and reflex control of the cardiovascular system. Two regions within the ventrolateral medulla were initially identified: the rostral ventrolateral medulla (RVLM) and the caudal ventrolateral medulla (CVLM). Activation of the RVLM raises arterial blood pressure and sympathetic nerve activity, and activation of the CVLM causes opposite effects. The RVLM premotor neurons project directly to sympathetic preganglionic neurons and are involved in the maintenance of resting sympathetic vasomotor tone. A significant proportion of tonic activity in the RVLM sympathetic premotor neurons is driven by neurons located in a third region of the ventrolateral medulla denominated caudal pressor area (CPA). The CPA is a pressor region located at the extreme caudal part of the ventrolateral medulla that appears to have an important role controlling the activity of RVLM neurons. In this brief review, we will address the importance of the ventrolateral medulla neurons for the generation of resting sympathetic tone related to arterial blood pressure control focusing on two regions, the RVLM and the CPA.