Control of respiration in fish, amphibians and reptiles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hypoxic cardiorespiratory reflexes in the facultative air-breathing fish jeju (Hoplerythrinus unitaeniatus): role of branchial O-2 chemoreceptors

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hypercarbic cardiorespiratory reflexes in the facultative air-breathing fish jeju (Hoplerythrinus unitaeniatus): the role of branchial CO2 chemoreceptors

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gill chemoreceptors and cardio-respiratory reflexes in the neotropical teleost pacu, Piaractus mesopotamicus

This study examined the location and distribution of O-2 chemoreceptors involved in cardio-respiratory responses to hypoxia in the neotropical teleost, the pacu (Piaractus mesopotamicus). Intact fish and fish experiencing progressive gill denervation by selective transection of cranial nerves IX and X were exposed to gradual hypoxia and submitted to intrabuccal and intravenous injections of NaCN while their heart rate, ventilation rate and ventilation amplitude were measured. The chemoreceptors producing reflex bradycardia were confined to, but distributed along all gill arches, and were sensitive to O-2 levels in the water and the blood. Ventilatory responses to all stimuli, though modified, continued following gill denervation, however, indicating the presence of internally and externally oriented receptors along all gill arches and either in the pseudobranch or at extra-branchial sites. Chemoreceptors located on the first pair of gill arches and innervated by the glossopharyngeal nerve appeared to attenuate the cardiac and respiratory responses to hypoxia. The data indicate that the location and distribution of cardio-respiratory O-2 receptors are not identical to those in tambaqui (Colossoma macropomum) despite their similar habitats and close phylogenetic lineage, although the differences between the two species could reduce to nothing more than the presence or absence of the pseudobranch.

The role of branchial and orobranchial O-2 chemoreceptors in the control of aquatic surface respiration in the neotropical fish tambaqui (Colossoma macropomum): progressive responses to prolonged hypoxia

The present study examined the role of branchial and orobranchial O-2 chemoreceptors in the cardiorespiratory responses, aquatic surface respiration (ASR), and the development of inferior lip swelling in tambaqui during prolonged (6 h) exposure to hypoxia. Intact fish (control) and three groups of denervated fish (bilateral denervation of cranial nerves IX+X (to the gills), of cranial nerves V+VII (to the orobranchial cavity) or of cranial nerves V alone), were exposed to severe hypoxia (Pw(O2) = 10 mmHg) for 360 min. Respiratory frequency (fR) and heart rate (fH) were recorded simultaneously with ASR. Intact (control) fish increased fR, ventilation amplitude (V-AMP) and developed hypoxic bradycardia in the first 60 min of hypoxia. The bradycardia, however, abated progressively and had returned to normoxic levels by the last hour of exposure to hypoxia. The changes in respiratory frequency and the hypoxic bradycardia were eliminated by denervation of cranial nerves IX and X but were not affected by denervation of cranial nerves V or V+VII. The VAMP was not abolished by the various denervation protocols. The fH in fish with denervation of cranial nerves V or V+VII, however, did not recover to control values as in intact fish. After 360 min of exposure to hypoxia only the intact and IX+X denervated fish performed ASR. Denervation of cranial nerve V abolished the ASR behavior. However, all (control and denervated (IX+X, V and V+VII) fish developed inferior lip swelling. These results indicate that ASR is triggered by O-2 chemoreceptors innervated by cranial nerve V but that other mechanisms, such as a direct effect of hypoxia on the lip tissue, trigger lip swelling.

Central control of cardiorespiratory interactions in fish

Fish control the relative flow rates of water and blood over the gills in order to optimise respiratory gas exchange. As both flows are markedly pulsatile, close beat-to-beat relationships can be predicted. Cardiorespiratory interactions in fish are controlled primarily by activity in the parasympathetic nervous system that has its origin in cardiac vagal. preganglionic neurons. Recordings of efferent activity in the cardiac vagus include units firing in respiration-related bursts. Bursts of electrical stimuli delivered peripherally to the cardiac vagus or centrally to respiratory branches of cranial, nerves can recruit the heart over a range of frequencies. So, phasic, efferent activity in cardiac vagi, that in the intact fish are respiration-related, can cause heart rate to be modulated by the respiratory rhythm. In elasmobranch fishes this phasic activity seems to arise primarily from central feed-forward interactions with respiratory motor neurones that have overlapping distributions with cardiac neurons in the brainstem. In teleost fish, they arise from increased levels of efferent vagal activity arising from reflex stimulation of chemoreceptors and mechanoreceptors in the orobranchial, cavity. However, these differences are largely a matter of emphasis as both groups show elements of feed-forward and feed-back control of cardiorespiratory interactions. (C) 2008 Elsevier GmbH. All rights reserved.

Síndrome de Garcin relacionada a linfoma não-Hodgkin

The complete unilateral cranial nerve paralysis syndrome, or Garcin 's Syndrome, is a rare clinical condition. The purpose of this paper is to describe a case associated with non-Hodgkin s lymphoma. A 41-year-old male patient developed a progressive cranial nerve disorder. On the right hand side, there was impairment of all cranial nerves. We report the clinical and laboratorial findings. Lymph node exeresis revealed a Diffuse Non-Hodgkin s Lymphoma, with diffuse hone marrow infiltration. Cerebrospinal fluid showed pleocytosis, with 100% of immunoblasts. The CT scan showed no tumoral masses on the brain stem. This is the first clinical description of a complete Garcin 's Syndrome caused by diffuse lymphomatous infiltration of the cranial nerves.

Morphology of the walls of the cavernous sinus of Cebus apella (tufted capuchin monkey)

The morphology of the dura mater and its relationship with the structures of the cavernous sinus were analyzed in five tufted capuchin monkeys (Cebus apella) using histological sections, showing that the walls of the cavernous sinus of this species are similar to those of other primates, including man. Except for the medial wall of the cavernous sinus, the remaining walls consist of two distinct dura mater layers. The deep layer of the lateral wall of the cavernous sinus is contiguous to the sheath of the oculomotor, trochlear and ophthalmic nerves. Arterioles, venules, venous spaces, neuronal bodies and nervous fiber bundles are found on this lateral wall.

Seqüência de moebius: Manifestações clínicas e avaliação auditiva

Introduction: Children with Moebius syndrome may present paralysis of cranial nerves III, IV, V, VI, VII, VIII, IX, X and XII, compromising motor and sensorial functions. Hands and feet defects (syndactyly, equinovarus and arthrogryposis) are frequently associated. These manifestations can be attributed to the use of misoprostol during pregnancy to induce abortion. Study design: Clinical prospective. Aim: To evaluate the main clinical manifestations, hearing acuity and possible etiologic factors in children with Moebius syndrome. Material and method: The children were submitted to clinical, otolaryngological and hearing acuity assessment. Hearing acuity was evaluated through behavioral tests, pure tone audiometry, tympanometry and auditory brainstem response (ABR). We investigated possible etiologic factors. Results: Three boys and two girls were evaluated. The main manifestations were: facial paralysis, paralysis of masseter muscle, defects in dental occlusion, retraction of tympanic membrane, equinovarus, oblique palpebral fissure and tongue atrophy. Conductive hearing loss was detected in three children and sensorineural hearing loss in one child. The use of misoprostol during pregnancy was reported by four mothers. Conclusions: The children with Moebius syndrome evaluated in the present study manifested palsies of various cranial nerves, especially V, VII and XII nerves, responsible for motor and sensorial alterations. Inadequate eustachian tube function associated to conductive hearing loss was frequent. The use of misoprostol during pregnancy was reported by the mothers and it was considered a possible etiologic factor.

Potencial cognitivo P300 em indivíduos com diabetes mellitus

Diabetes Mellitus may lead to alterations in the eyes, kidneys, cranial nerves, peripheral nerves, ears etc. The cognitive function, also, seems to be compromised in subjects presented with Diabetes Mellitus, since the cortical and subcortical structures responsible for this function are hindered in some insulin-dependent patients. The cognitive potential P300 has been used as an objective procedure to assess cerebral cognitive functions. Objective: Analyze the sensitivity of P300 cognitive potential for the detection of alterations on the auditory cortex secondary to Diabetes Mellitus. Study design: transversal cohort. Material and Method: Sixteen diabetic subjects of both genders aged 7 to 71 years, and seventeen non-diabetic individuals at the same age range participated in this study, the evaluation procedures were pure tone audiometry (PTA) and P300 cognitive potential. Glycemia of the group presented with Diabetes was assessed prior to applying the P300. Results: No statistically significant difference was shown for the PTA results. A statically significant difference was observed between groups when analyzing the latency of the P300 component measured in Fz. there was a correlation between glycemia and the latency and amplitude of P300. Conclusion: The investigation of the cognitive potential of P300 is an important procedure for the prevention and early diagnosis of neurological changes in individuals presented with Diabetes Mellitus.

Trigeminal neuralgia: Literature review

The trigeminal nerve, fifth equal of cranial nerves, a mixed nerve is considered by possessing motor and sensitive components. The sensitive portion takes to the Nervous System Central somesthesics information from the skin and mucous membrane of great area of the face, being responsible also for a neural disease, known as the Trigeminal Neuralgia. The aim of this study was to review the literature on the main characteristics of Trigeminal Neuralgia, the relevant aspects for the diagnosis and treatment options for this pathology. This neuralgia is characterized by hard pains and sudden, similar to electric discharges, with duration between a few seconds to two minutes, in the trigeminal nerve sensorial distribution. The pain is unchained by light touches in specific points in the skin of the face or for movements of the facial muscles, it can be caused by traumatic sequels or physiologic processes degenerative associate the vascular compression. Prevails in the senior population, frequently in the woman. In a unilateral way it attacks more the maxillary and mandibular divisions, rarely happens in a simultaneous way in the three branches of trigeminal nerve three branches.

Alterações odontológicas em pacientes urêmicos em hemodiálise e suas possíveis correlações com neuropatias de nervos cranianos

Pós-graduação em Bases Gerais da Cirurgia - FMB

Estratégias de reparo utilizadas na substituição de segmento consonantal em portadores da síndrome de Moebius: uma análise otimalista

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Immunolocalization of myosin Va in the developing nervous system of embryonic chicks

Myosins are molecular motors associated with the actin cytoskeleton that participate in the mechanisms of cellular motility. During the development of the nervous system, migration of nerve cells to specific sites, extension of growth cones, and axonal transport are dramatic manifestations of cellular motility. We demonstrate, via immunoblots, the expression of myosin Va during early stages of embryonic development in chicks, extending from the blastocyst period to the beginning of the fetal period. The expression of myosin Va in specific regions and cellular structures of the nervous system during these early stages was determined by immunocytochemistry using a polyclonal antibody. Whole mounts of chick embryos at 24-30-h stages showed intense immunoreactivity of the neural tube in formation along its full extent. Cross-sections at these stages of development showed strong labeling in neuroepithelial cells at the basal and apical regions of the neural tube wall. Embryos at more advanced periods of development (48h and 72 h) showed distinctive immunolabeling of neuroepithelial cells, neuroblasts and their cytoplasmic extensions in the mantle layer of the stratified neural tube wall, and neuroblasts and their cytoplasmic extensions in the internal wall of the optic cup, as well as a striking labeling of cells in the apparent nuclei of cranial nerves and budding fibers. These immunolocalization studies indicate temporal and site-specific expression of myosin Va during chick embryo development, suggesting that myosin Va expression is related to recruitment for specific cellular tasks.

Pseudoaneurysm of the internal carotid artery presenting with massive (recurrent) epistaxes: a life-threatening complication of craniofacial trauma

Vascular lesions can be serious complications resulting of blunt or penetrating trauma(1,2). Internal carotid artery lesion is one of most serious and relatively frequent in all mechanisms of craniofacial trauma. Several clinical manifestations can occur as central neurologic and cranial nerves deficits as well as several degrees of bleeding (from mild symptomatic to fatal). Recurrent and massive epistaxis can occur after trauma due to pseudaoneurysms of the external and internal carotid artery (ICA)(3,4). Considering its life-threatening course, the assisting physician has a relatively narrow time to detect and treat these lesions.We present two cases of recurrent and massive epistaxis secondary to ICA pseudoaneurysm following blunt and perforating trauma. Evolution was fatal in the first case with delayed treatment and uneventfully in the second which was treated by occlusion of the pseudoaneurysm and ICA via endovascular intervention.