RESUMO
The simpler nervous systems of certain invertebrates provide opportunities to examine colocalized classical neurotransmitters in the context of identified neurons and well defined neural circuits. This study examined the distribution of γ-aminobutyric acid-like immunoreactivity (GABAli) in the nervous system of the panpulmonates Biomphalaria glabrata and Biomphalaria alexandrina, major intermediate hosts for intestinal schistosomiasis. GABAli neurons were localized in the cerebral, pedal, and buccal ganglia of each species. With the exception of a projection to the base of the tentacle, GABAli fibers were confined to the CNS. As GABAli was previously reported to be colocalized with markers for dopamine (DA) in five neurons in the feeding network of the euopisthobranch gastropod Aplysia californica (Díaz-Ríos, Oyola, & Miller, 2002), double-labeling protocols were used to compare the distribution of GABAli with tyrosine hydroxylase immunoreactivity (THli). As in Aplysia, GABAli-THli colocalization was limited to five neurons, all of which were located in the buccal ganglion. Five GABAli-THli cells were also observed in the buccal ganglia of two other intensively studied panpulmonate species, Lymnaea stagnalis and Helisoma trivolvis. These findings indicate that colocalization of the classical neurotransmitters GABA and DA in feeding central pattern generator (CPG) interneurons preceded the divergence of euopisthobranch and panpulmonate taxa. These observations also support the hypothesis that heterogastropod feeding CPG networks exhibit a common universal design.
Assuntos
Biomphalaria/metabolismo , Músculos/inervação , Músculos/fisiologia , Tirosina 3-Mono-Oxigenase/metabolismo , Ácido gama-Aminobutírico/metabolismo , Animais , Geradores de Padrão Central/fisiologia , Extremidades/inervação , Extremidades/fisiologia , Comportamento Alimentar , Gânglios dos Invertebrados/citologia , Gânglios dos Invertebrados/fisiologia , Imuno-Histoquímica , Interneurônios/fisiologia , Lymnaea , Músculos/metabolismo , Fibras Nervosas/fisiologia , Neurônios/fisiologia , Especificidade da EspécieRESUMO
The success of a microneurosurgical intervention in leprous neuropathy (LN) depends on the diagnosis of chronic compression before irreversible paralysis and digital loss occurs. In order to determine the effectiveness of a different approach for early identification of LN, neurosensory testing with the Pressure-Specified Sensory Device™ (PSSD), a validated and sensitive test, was performed in an endemic zone for leprosy. A cross-sectional study was conducted to analyze a patient sample meeting the World Health Organization (WHO) criteria for Hansen's disease. The prevalence of LN was based on the presence of ≥1 abnormal PSSD pressure threshold for a two-point static touch. A total of 312 upper and lower extremity nerves were evaluated in 39 patients. The PSSD found a 97.4% prevalence of LN. Tinel's sign was identified in 60% of these patients. An algorithm for early identification of patients with LN was proposed using PSSD testing based on the unilateral screening of the ulnar and deep peroneal nerves.
Assuntos
Extremidades/inervação , Hanseníase , Síndromes de Compressão Nervosa , Exame Neurológico , Procedimentos Neurocirúrgicos/métodos , Adulto , Idoso de 80 Anos ou mais , Algoritmos , Criança , Estudos Transversais , Diagnóstico Precoce , Equador/epidemiologia , Feminino , Humanos , Hanseníase/complicações , Hanseníase/epidemiologia , Masculino , Síndromes de Compressão Nervosa/diagnóstico , Síndromes de Compressão Nervosa/etiologia , Síndromes de Compressão Nervosa/fisiopatologia , Exame Neurológico/instrumentação , Exame Neurológico/métodos , Seleção de Pacientes , Limiar Sensorial , TatoRESUMO
The adult salamander has been studied as a model for regeneration of complex tissues for many decades. Only recently with the development of gain-of-function assays for regeneration, has it been possible to screen for and assay the function of the multitude of signaling factors that have been identified in studies of embryonic development and tumorigenesis. Given the conservation of function of these regulatory pathways controlling growth and pattern formation, it is now possible to use the functional assays in the salamander to test the ability of endogenous as well as small-molecule signaling factors to induce a regenerative response.
Assuntos
Ambystoma mexicanum/metabolismo , Extremidades , Regeneração , Transdução de Sinais , Animais , Modelos Animais de Doenças , Extremidades/lesões , Extremidades/inervação , Transplante de Pele , Cicatrização , Ferimentos e Lesões/etiologiaRESUMO
Motor cortex stimulation (MCS) is used as a therapy for patients with refractory neuropathic pain. Experimental evidence suggests that the motor cortex (MC) is involved in the modulation of normal nociceptive response, but the underlying mechanisms have not been clarified yet. In previous studies, we demonstrated that MCS increases the nociceptive threshold of naive conscious rats by inhibiting thalamic sensory neurons and disinhibiting the neurons in periaqueductal gray (PAG), with the involvement of the opioid system. The aim of this study was to investigate the possible somatotopy of the motor cortex on MCS-induced antinociception and the pattern of neuronal activation evaluated by Fos and Egr-1 immunolabel in an attempt to better understand the relation between MC and analgesia. Rats received epidural electrode implants placed over the MC, in three distinct areas (forelimb, hindlimb or tail), according to a functional mapping established in previous studies. Nociceptive threshold was evaluated under 15-min electrical stimulating sessions. MCS induced selective antinociception in the limb related to the stimulated cortex, with no changes in other evaluated areas. MCS decreased Fos immunoreactivity (Fos-IR) in the superficial layers of the dorsal horn of the spinal cord for all evaluated groups and increased Fos-IR in the PAG, although no changes were observed in the PAG for the tail group. Egr-1 results were similar to those obtained for Fos. Data shown herein demonstrate that MCS elicits a substantial and selective antinociceptive effect, which is mediated, at least in part, by the activation of descendent inhibitory pain pathway.
Assuntos
Estimulação Elétrica/métodos , Hiperalgesia/terapia , Córtex Motor/fisiologia , Limiar da Dor/fisiologia , Análise de Variância , Animais , Modelos Animais de Doenças , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Eletrodos , Extremidades/inervação , Membro Anterior/fisiopatologia , Lateralidade Funcional , Regulação da Expressão Gênica/fisiologia , Masculino , Nociceptores/fisiologia , Proteínas Oncogênicas v-fos/metabolismo , Medição da Dor , Substância Cinzenta Periaquedutal/metabolismo , Estimulação Física/efeitos adversos , Ratos , Ratos Wistar , Método Simples-Cego , Medula Espinal/metabolismo , Medula Espinal/patologia , Fatores de TempoRESUMO
Amphibians can regenerate missing body parts, including limbs. The regulation of collagen has been considered to be important in limb regeneration. Collagen deposition is suppressed during limb regeneration, so we investigated collagen deposition and apical epithelial cap (AEC) formation during axolotl limb regeneration. The accessory limb model (ALM) has been developed as an alternative model for studying limb regeneration. Using this model, we investigated the relationship between nerves, epidermis, and collagen deposition. We found that Sp-9, an AEC marker gene, was upregulated by direct interaction between nerves and epidermis. However, collagen deposition hindered this interaction, and resulted in the failure of limb regeneration. During wound healing, an increase in deposition of collagen caused a decrease in the blastema induction rate in ALM. Wound healing and limb regeneration are alternate processes.
Assuntos
Ambystoma mexicanum/fisiologia , Colágeno/fisiologia , Regeneração/fisiologia , Animais , Extremidades/inervação , Extremidades/fisiologia , Botões de Extremidades/fisiologia , Pele/inervação , Fenômenos Fisiológicos da PeleAssuntos
Humanos , Bloqueio Nervoso/instrumentação , Bloqueio Nervoso/métodos , Dor Pós-Operatória/terapia , Ortopedia , Adjuvantes Anestésicos/administração & dosagem , Anestésicos Locais/administração & dosagem , Extremidades/inervação , Nervos Periféricos/anatomia & histologia , Nervos Periféricos/irrigação sanguíneaRESUMO
Metamizol (dipyrone) and other nonsteroidal anti-inflammatory drugs (NSAIDs) induce antinociception by acting upon peripheral tissues and upon central nervous system structures, notably the periaqueductal grey matter (PAG) and the spinal cord. Inflammation-induced hyperalgesia is prevented by spinal application of NSAIDs before the inflammation, but once central sensitization is established the spinal effect of NSAIDs is uncertain. The present study examines whether the action upon the PAG contributes to the attenuation of inflammation-induced spinal hyperalgesia by NSAIDs. In deeply anaesthetized rats, responses of spinal multireceptive neurons to mechanical stimulation of the ipsilateral paw and leg were recorded. An inflammation in the paw was induced with carrageenan. Fifty minutes later, neuronal responses to innocuous and noxious stimulation had, respectively, increased to 206 and 304% for paw, and 160 and 190% for leg. When metamizol (150 microg in 0.5 microL) was microinjected into PAG before the inflammation, neuronal hyperexcitability was delayed for approximately 60 min and was much reduced by 215 min. More interestingly, microinjection of metamizol into PAG when hyperexcitability was fully developed depressed neuronal responses down to baseline for approximately 1 h. The effect of PAG metamizol was reversed by microinjection of a GABA(A) agonist into the rostral ventromedial medulla (RVM), which indicates that RVM relays the metamizol effect from PAG onto the spinal cord. These results suggest that, upon clinical administration of NSAIDs, a joint action upon PAG and spinal cord contributes to preventing the development of hyperalgesia but it is mainly the action upon PAG which contributes to reducing fully established hyperalgesia.
Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Dipirona/uso terapêutico , Hiperalgesia/prevenção & controle , Bulbo/efeitos dos fármacos , Substância Cinzenta Periaquedutal/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Extremidades/inervação , Hiperalgesia/etiologia , Inflamação/complicações , Inflamação/etiologia , Laminectomia/métodos , Masculino , Bulbo/fisiopatologia , Microinjeções , Neurônios Aferentes/efeitos dos fármacos , Medição da Dor , Substância Cinzenta Periaquedutal/fisiopatologia , Ratos , Ratos Sprague-Dawley , Medula Espinal/patologiaRESUMO
The present report compares the morphology of callosal axon arbors projecting from and to the hind- or forelimb representations in the primary somatosensory cortex (SI) of the agouti (Dasyprocta primnolopha), a large, lisencephlic Brazilian rodent that uses forelimb coordination for feeding. Callosal axons were labeled after single pressure (n = 6) or iontophoretic injections (n = 2) of the neuronal tracer biotinylated dextran amine (BDA, 10 kD), either into the hind- (n = 4) or forelimb (n = 4) representations of SI, as identified by electrophysiological recording. Sixty-nine labeled axon fragments located across all layers of contralateral SI representations of the hindlimb (n = 35) and forelimb (n = 34) were analyzed. Quantitative morphometric features such as densities of branching points and boutons, segments length, branching angles, and terminal field areas were measured. Cluster analysis of these values revealed the existence of two types of axon terminals: Type I (46.4%), less branched and more widespread, and Type II (53.6%), more branched and compact. Both axon types were asymmetrically distributed; Type I axonal fragments being more frequent in hindlimb (71.9%) vs. forelimb (28.13%) representation, while most of Type II axonal arbors were found in the forelimb representation (67.56%). We concluded that the sets of callosal axon connecting fore- and hindlimb regions in SI are morphometrically distinct from each other. As callosal projections in somatosensory and motor cortices seem to be essential for bimanual interaction, we suggest that the morphological specialization of callosal axons in SI of the agouti may be correlated with this particular function.
Assuntos
Axônios/ultraestrutura , Corpo Caloso/citologia , Extremidades/inervação , Vias Neurais/citologia , Roedores/anatomia & histologia , Córtex Somatossensorial/citologia , Animais , Axônios/fisiologia , Biotina/análogos & derivados , Corpo Caloso/fisiologia , Dextranos , Extremidades/fisiologia , Membro Anterior/inervação , Membro Anterior/fisiologia , Masculino , Destreza Motora/fisiologia , Movimento/fisiologia , Vias Neurais/fisiologia , Terminações Pré-Sinápticas/fisiologia , Roedores/fisiologia , Córtex Somatossensorial/fisiologia , Especificidade da Espécie , Tato/fisiologiaRESUMO
There is no clear definition on the role of sympathetic skin response (SSR) in the evaluation of patients with Parkinson's disease (PD). We recorded the SSR of the palms of 64 controls and 46 patients with PD to electrical stimulation of the median nerve at the wrist. We analyzed onset latency and peak-to-peak amplitude. A study of parasympathetic function (R-R interval analysis) was also undertaken. We found that patients with PD had more absent SSRs than controls. The mean amplitude of the SSR was significantly reduced in both lower and upper limbs of PD patients in comparison with control subjects (p<0.001). The onset latency was longer in the lower limbs of these patients in respect to the control group (p<0.003). There was a significant inverse correlation between SSR amplitudes and age, severity and late onset of the disease. There was no association of these parameters with dysautonomic symptoms or R-R interval variation. In conclusion, there is a significant association between altered SSR and PD and an inverse correlation in this group of patients between SSR values and older age, greater severity and later onset of disease. Therefore, the study of SSR may provide valuable information on cholinergic sympathetic function in patients with PD.
Assuntos
Resposta Galvânica da Pele/fisiologia , Doença de Parkinson/fisiopatologia , Pele/inervação , Sistema Nervoso Simpático/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Estimulação Elétrica/métodos , Extremidades/inervação , Extremidades/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tempo de Reação/fisiologia , Tempo de Reação/efeitos da radiação , Estudos Retrospectivos , Pele/efeitos da radiação , Estatísticas não Paramétricas , Sistema Nervoso Simpático/efeitos da radiaçãoRESUMO
Backfills of the cerebral-buccal connective (CBC) of Aplysia californica revealed a cluster of five to seven pedal-buccal projection neurons in the anterolateral quadrant of the ventral surface of each pedal ganglion. Intra- and extracellular recordings showed that the pedal-buccal projection neurons shared common electrophysiological properties and synaptic inputs. However, they exhibited considerable heterogeneity with respect to their projection patterns. All pedal-buccal projection neurons that were tested received a slow excitatory postsynaptic potential from the ipsi- and contralateral cerebral-pedal regulator (C-PR) neuron, a cell that is thought to play a key role in the generation of a food-induced arousal state. Tests were conducted to identify potential synaptic follower neurons of the pedal-buccal projection neurons in the cerebral and buccal ganglia, but none were detected. Finally, nerve recordings revealed projections from the pedal-buccal projection neurons in the nerves associated with the buccal ganglion. In tests designed to determine the functional properties of these peripheral projections, no evidence was obtained supporting a mechanosensory or proprioceptive role and no movements were observed when they were fired. It is proposed that peripheral elements utilized in consummatory phases of Aplysia feeding may be directly influenced by a neuronal pathway that is activated during the food-induced arousal state.