59 resultados para mamíferos terrestres


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Collembola is one of the most abundant and diverse group of terrestrial arthropods, being at the base of the food chain operating in the decomposition process. They have a wide distribution in the world and can be found in practically all habitats. The knowledge of this distinctive fauna is still deficient in brazilian territory, especially in semi-arid region. The aim of this study was to investigate which climatic variables may act as predictors of species richness, abundance of individuals and compositional structure of the taxocenose of Collembola over 12 months in an area dominated by semi-arid Caatinga vegetation, northeastern Brazil and describe new species of the genus Seira found, more diverse taxon of Collembola in Brazil. Samples were collected in João Câmara, Rio Grande do Norte. Ten plots of 20 x 20 meters were established and the specimens were collected with collection effort of one hour/people using entomological aspirator. The identification and description of the species was carried out by studying the morphology and chaetotaxy. Was performed a multiple regression analysis between species richness and abundance of individuals with climatic variables. A total of 1231 individuals belonging to 15 species, 12 genera and nine families. The greatest richness and abundance of Collembola were found during the rainy season. The genus Seira was the most abundant. Rainfall explained the temporal variation in species richness and abundance of Collembola in the semi-arid region, which is consistent with the biology of these animals. The populations of Collembola showed grouped distribution. Three new species of Seira were described and illustrated and all show similarities with species already registered in the national territory

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Arbuscular mycorrhizal fungi (AMF) are obligatory symbiotic organisms that associate with roots of a large number of plant taxa, and are found in all terrestrial ecosystems. These fungi promote greater tolerance to environmental stresses to associated plant, favoring the establishment of plant communities, especially where soil fertility is a limiting factor, as in the Caatinga, an exclusively Brazilian domain that has been focus of research due to its great biodiversity that can help clarify the history of vegetation in South America. Because of the ecological importance of AMF, the limited number of jobs and the potential diversity of the Caatinga, this work aims to inventory the diversity and determine AMF communities in areas with different faces occurrent in FLONA Araripe, Ceará (CE). The sample collection occurred in four periods at the beginning and end of the dry season (August and December 2011, respectively) and rainy (February and June 2012, respectively) in an area of marsh and woodland altitude of the Araripe, Crato, CE. The glomerosporos were extracted by wet sieving and centrifugation in water and sucrose (50%) mounted between slide and coverslip using PVLG and PVLG + Reagent Melzer. In total, we found 46 species of AMF distributed in eight families and 16 genera: Acaulospora (6), Ambispora (1), Cetraspora (2), Dentiscutata (5), Fuscutata (2), Gigaspora (6), Glomus (13) Intraornatospora (1), Kuklospora (1), Orbispora (1), Paradentiscutata (1), Quatunica (1), Racocetra (1), Scutellospora (2), Septoglomus (2) and a new genus. analysis showed that ecological each area of study has its own seasonal dynamics, with an area of woodland with a greater diversity of species throughout the year, while the marsh elevation showed greater variation in species found among the collection periods, showing that vegetation and rainfall has strong influence on the seasonal dynamics of AMF, as well as the availability of nutrients and soil pH so

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Collembola is one of the most abundant and diverse group of terrestrial arthropods, being at the base of the food chain operating in the decomposition process. They have a wide distribution in the world and can be found in practically all habitats. The knowledge of this distinctive fauna is still deficient in brazilian territory, especially in semi-arid region. The aim of this study was to investigate which climatic variables may act as predictors of species richness, abundance of individuals and compositional structure of the taxocenose of Collembola over 12 months in an area dominated by semi-arid Caatinga vegetation, northeastern Brazil and describe new species of the genus Seira found, more diverse taxon of Collembola in Brazil. Samples were collected in João Câmara, Rio Grande do Norte. Ten plots of 20 x 20 meters were established and the specimens were collected with collection effort of one hour/people using entomological aspirator. The identification and description of the species was carried out by studying the morphology and chaetotaxy. Was performed a multiple regression analysis between species richness and abundance of individuals with climatic variables. A total of 1231 individuals belonging to 15 species, 12 genera and nine families. The greatest richness and abundance of Collembola were found during the rainy season. The genus Seira was the most abundant. Rainfall explained the temporal variation in species richness and abundance of Collembola in the semi-arid region, which is consistent with the biology of these animals. The populations of Collembola showed grouped distribution. Three new species of Seira were described and illustrated and all show similarities with species already registered in the national territory

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Edaphic ecosystems are the basis for the production of terrestrial biological resources and their dynamics affect not only the natural environment but also society and their economic activities. In Caatinga biome, the semi-arid climate associated with an inadequate soil management has increased the degradation and loss of productive potential of the soil. In this context, the study of soil fauna, including springtails, becomes an important indicator of soil quality. This study aimed to evaluate the fauna of Collembola in an area of Caatinga of Rio Grande do Norte State and the influence of biotic and abiotic factors, such as soil, vegetation and climate characteristics, on the structure of the taxocenosis. The environmental variables which were used were the following ones: granulometry (represented by the proportion of sand), quantity of organic matter and soil pH, richness, density and aerial biomass of the vegetal structure, and necromass. We used pitfall traps intending to collect specimens of the epiedaphic fauna of Collembola in 30 points located on Cauaçu Farm, João Câmara, RN, in July (rainy season) and November (dry season) 2011. We collected 5513 individuals of 15 species distributed in 13 genera and 9 families of Collembola. Five of the recorded species are new to science, confirming the expected high degree of endemism for Caatinga biome, and the highest abundance was recorded in the rainy season, which suggests Collembola sensitivity to low humidity. Four species were more abundant in the dry season, all of them belonged to the Order Entomobryomorpha. Results of statistical analyzes suggest that plant species richness, aerial biomass of vegetal structure, proportion of sand in the soil, pH and humidity are the main influences to the abundance of Collembola in the region studied

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Northeastern Brazil is mainly formed by crystalline terrains (around 60% in area). Moreover, this region presents a semi-arid climate so that it is periodically subject to drought seasons. Furthermore, ground water quality extracted fromwells usually presents poor quality because of their high salinity contents. Nevertheless, ground water is still a very important source of water for human and animal consumption in this region. Well sitting in hard rocks terrains in Northeastern Brazil offers a mean success index of aboul 60%, given that a successful siting is defined by a well producing at least 0.5 m³/h. This low index reveals lack of knowledga about the true conditions of storage and percolation of ground water in crystalline rocks. Two models for structures storing and producing ground water in crystalline rocks in Northeastem Brazil have been proposed in the literature. The first model,tradnionally used for well sitting since the sixties are controlled by faults or fractures zones. This model is commonly referred, in Brazilian hydrogeological literature, as the "creek-crack" model (riacho-fenda in Portuguese). Sites appearing to present dense drainage network are preferred for water well siting - particularly at points where the drainages cross-cul each other. Field follow up work is usually based only on geological criteria. The second model is the "eluvio-alluvial through" (calha eluvio-aluvionar in Portuguese); it is also described in the literature but it is not yet incorporated in well sitting practice. This model is based on the hypothesis that reclilinear drainages can also be controlled by the folietion of the rock. Eventually, depending upon the degree of weathering, a through-shaped structure filled with sediments (alluvium and regolith) can be developed which can store and water can be produced from. Using severalfield case studies, this Thesis presents a thorough analysis ofthe two above cited models and proposes a new model. The analysis is based on an integrated methodological approach using geophysics and structural geology. Both land (Resitiviy and Ground Penetrating Radar- GPR) and aerogeophysical (magnetics and frequency domain eletromagnetics) surveys were used. Slructural analysis emphasized neolectonic aspects; in general, itwas found that fractures in the E-W direction are relatively open, as compared to fracturas inthe N-S direction, probably because E-W fractures were opened by the neotectonic stress regime in Northeastern Brazil, which is controlled by E-W compression and N-S extension. The riacho-fenda model is valid where drainages are controlled by fractures. The degree of fracturing and associated weathering dictale the hydrogeological potential of the structure. Field work in structural analogues reveals that subvertical fractures show consistent directions both in outcrop and aerophotograph scales. Geophysical surveys reveal subvertical conductive anomalies associated to the fracture network controlling the drainage; one of the borders of the conductive anomaly usually coincide wih the drainage. An aspect of particular importance to the validation of fracture control are the possible presence of relalively deep conductive anomalies wihoul continuation or propagalion to the surface. The conductive nature of lhe anomaly is due to the presence of wealhered rock and sedirnenls (alluvium and/or regolilh) storing ground waler which occur associated to the fracture network. Magnetic surveys are not very sensisnive to these structures.lf soil or covering sedirnents are resislive (> 100 Ohm.m), GPR can ba used to image precisely lhe fracture network. A major limialion of riacho-fenda model, revealed by GPR images, is associated to the fact thal subhorizontal fractures do play a very important role in connecting the fracture network, besides connect shallow recharge zones to relalively deep subvertical frecture zones. Iffractures play just a secondary control on the drainage, however, r/acho-fenda model may have a very limiled validny; in these cases, large portions oflhe drainage do nol coincide wilh frectures and mosl oflhewells localed in lhe drainage surrounding would resull dry. Usually, a secondary conlrol on lhe drainage by Ihefraclure networkcan be revealed only wilh detailed geophysical survey. The calha elClv1o-aluvlonarmodel is valid where drainages are conlrolled by folialion. The degree 01 wealhering 01 lhe lolialion planes dictales lhe hydrogeological polenlial 01 lhe slruclure. Outcrop analysis reveals Ihal lolialion and drainage direclions are parallel and Ihal no Iraclures, orfraclures wilh diflerent directions 01 lhe drainage direclion occur. Geophysical surveys reveal conduclive anomalies in a slab lorm associaled 10 lhe Ihrough 01 lhe wealhered rock and sedimenls (alluvium and/or regolith). Magnelic surveys can ofler a very good conlrol on lolialion direclion. An importanl aspect 10 validale lolialion conlrol are lhe presence 01 conductive anomalies showing shallow and deep portions area which are linked. Illhere is an exlensive soil cover, r/acho-fenda and calha eIClv1o-aluv/onar conlrols can be easily misinlerpreled in lhe absence 01 geophysical conlrol. Certainly, Ihis lacl could explain at leasl a part of lhe failure index in well sitting. The model wealhering sack (bolsllo de Intempertsmo in Portuguese) is proposed to explain cases where a very inlensive wealhering occur over lhe crystalline rock so Ihal a secondary inlerslilial porosity is crealed. The waler is Ihen stored in lhe porous of lhe regolilh in a similar mannerlo sedimentary rocks. A possible example ofthis model was delecled by using land geophysical survey where a relalivelyvery deep isolaled conduclive anomaly, in a slab form, was delected. Iflhis structure does store ground waler, certainly Ihere must be a link 01 lhe deep slructure wilh lhe surface in orderlo provide walerfeeding. This model mighl explain anomalous waler yields as greal as 50 m³/h Ihalsomelimescan occur in crystalline rocks in Northeaslern Brazil

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The circadian behavior associated with the 24 hours light-dark (LD) cycle (T24) is due to a circadian clock , which in mammals is located in the hypothalamic suprachiasmatic nucleus (SCN). Under experimental conditions in which rats are espoused to a symmetric LD 22h cycle (T22) the two SCN regions, ventrolateral (vl) and dorsomedial (dm), can be functionally isolated, suggesting that each region regulates distinct physiological and behavioral components. The vl region regulates the locomotor activity and slow wave sleep (SWS) rhythms, while the dm region assures the body temperature and paradoxical sleep (PS) rhythms regulation. This research aimed to deepen the knowledge on the functional properties of circadian rhythmicity, specifically about the internal desynchronization process, and its consequences to locomotor activity and body temperature rhythms as well as to the sleep-wake cycle pattern in rats. We applied infrared motion sensors, implanted body temperature sensors and a telemetry system to record electrocorticogram (ECoG) and electromyogram (EMG) in two rat groups. The control group under 24h period LD cycle (T24: 12hL-12hD) to the baseline record and the experimental group under 22h period LD cycle (T22: 11hL- 11hD), in which is known to occur the uncoupling process of the circadian locomotor activity rhythm where the animals show two distinct locomotor activity rhythms: one synchronized to the external LD cycle, and another expressed in free running course, with period greater than 24h. As a result of 22h cycles, characteristic locomotor activity moment appear, that are coincidence moments (T22C) and non coincidence moments (T22NC) which were the main focus or our study. Our results show an increase in locomotor activity, especially in coincidence moments, and the inversion of locomotor activity, body temperature, and sleep-wake cycle patterns in non coincidence moments. We can also observe the increase in SWS and decrease in PS, both in coincidence and non coincidence moments. Probably the increases in locomotor activity as a way to promote the coupling between circadian oscillators generate an increased homeostatic pressure and thus increase SWS, promoting the decreasing in PS

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In February 2011, the National Agency of Petroleum, Natural Gas and Biofuels (ANP) has published a new Technical Rules for Handling Land Pipeline Petroleum and Natural Gas Derivatives (RTDT). Among other things, the RTDT made compulsory the use of monitoring systems and leak detection in all onshore pipelines in the country. This document provides a study on the method for detection of transient pressure. The study was conducted on a industrial duct 16" diameter and 9.8 km long. The pipeline is fully pressurized and carries a multiphase mixture of crude oil, water and natural gas. For the study, was built an infrastructure for data acquisition and validation of detection algorithms. The system was designed with SCADA architecture. Piezoresistive sensors were installed at the ends of the duct and Digital Signal Processors (DSPs) were used for sampling, storage and processing of data. The study was based on simulations of leaks through valves and search for patterns that characterize the occurrence of such phenomena

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The study area consist in high sensitivity environments located on the northern coast of Rio Grande do Norte, Northeast Brazil. The barrier island are the main geomorphological features on the coastal landscape, being naturally instable and surrounded by industrial activities like oil fields, salt industry, shrimp farms and urban areas sometimes installed parallel to the coast, combined with coast engineering interventions. High energy hydrodynamic process are responsible for the morphological instability of the coast. The study was based on remote sensing data obtained between 1954 and 2007 which consist in orbital images from Landsat, CBERS and Ikonos satellites and aerial photos. With all data integrated on GIS environment it was possible to update thematic maps of geology, geomorphology, vegetation, soil and landuse and development of multitemporal maps pointing areas with erosion and depositions of sediments, defining the critical erosion process on this region. The bigger morphological changes are related to changes on wind patterns during the year, terrestrial and sea breezes during the day, with spits and barrier island migration, opening and closing of channels like the one parallel to the coast on the area of Serra and Macau oil fields. These factors combined with the significant reduction on sediment budgets due to the loss of natural spaces to sediment reworking contribute to the low resilience which tends to be growing on the area of Serra and Macau oil fields. In front of such scenery a detailed monitoring was done in order to find technological possibilities for coastal restoration. A pilot area was defined to start the project of mangrove restore together with beach nourishment in order to minimize the effect of the erosion caused by the channel parallel to the coast, contributing to stabilize the northeast channel as the main one. It s expected that such methodology will aid the coastal environments restoration and the balance between industrial activities and coastal erosion

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Theta rhythm consists of an electrophysiological hippocampal oscillation present in mammalian species (4-12 Hz with variations across species). This oscillation is present during active waking and is also prevalent in local field potentials (LFP) during rapid eye movement sleep (REM sleep). Several studies have shown that theta rhythm is important in cognitive tasks and that the medial septum is a key region for its occurrence. The septum sends cholinergic, GABAergic and glutamatergic projections to the hippocampus, which in turn projects axons to the septum. Besides the septum, other regions are involved in regulating theta rhythm, forming a complex network of interactions among brain areas that result in theta rhythm. Optogenetics is a recently developed method that has been widely used in various research areas. It allows us to manipulate the electrical activity of neurons through light stimulation. One of the existing techniques consists in using a viral vector to induce the neuronal expression of ion channels associated with the light-sensitive molecule rhodopsin (e.g. ChR2). Once infected, the neurons become sensitive to light of a particular wavelength. The present M. Sc. research aimed to perform luminous stimulation of the brain in anesthetized and freely behaving animals using chronically implanted electrodes and optical fibers in animals infected with a viral vector for ChR2 expression. Surgical viral injections were performed in the medial septum; histological results confirmed the expression of ChR2 by way of the presence of the eYFP reporter protein in the septum and also in hippocampal processes. Moreover, we performed acute experiments with luminous stimulation of the medial septum and LFP recordings of the septum and hippocampus of anesthetized animals. Action potentials were recorded in the septum. In these experiments we observed a significant increase in the firing rates of septal neurons during luminous stimulation (n = 300 trials). Furthermore, we found an early light-evoked response in the hippocampal LFP. Chronic experiments with luminous stimulation of the medial septum and hippocampus in freely behaving animals were also performed in combination with LFP recordings. We found that the luminous stimulation of the septum is able to induce theta rhythm in the hippocampus. Together, the results demonstrate that the luminous stimulation of the medial septum in optogenetically-modified animals causes relevant electrophysiological changes in the septum and the hippocampus.

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The circadian timing system (CTS), in rodents, consists of interconnected neural structures such as the suprachiasmatic nucleus (SCN) of the hypothalamus, Intergeniculate Leaflet (IGL) of the thalamus, synchronous pathways and behavioral effectors. The SCN has been described as the major circadian pacemaker in several species of mammals, while the IGL appears to be involved in integration of photic and non-photic clues relaying them to SCN. The CTS allows an ordered internal temporal organization to the organism, providing the proper execution of physiological and behavioral mechanisms, which brings homeostasis. However, this stability is disrupted with aging process causing numerous pathological disorders, ranging from simple loss of physiological functions to decreases in cognitive performance. Therefore, is fundamental understanding the effects of senescence in this system. In this context, is proposed in this study to check if there are changes in IGL cytoarchitecture, neurochemical and retinal afferent markers with aging and their possible morpho-functional implications. To achieve this goal wistar rats were divided into 3 groups: young (3 months); Middle Age (13 months); Old (23 months). They were submitted to paraformaldhyde (4%) transcardiac perfusion to tissue fixation. Then, they had their brain removed and sectioned in 30 µm slices, which every sixth section were collected. This sections were processed by nissl method and immunostaining for GFAP, GAD, ENK, NPY and CTb in order to analyze the IGL features. It was observed a cell loss in middle age and old animals at Nissl, NPY and CTb stains. In addition, it was shown a increase in GFAP in middle aged animals compared to young and old ones. No differences were found in other neurochemichal stains. These data suggests IGL loss retinal afferents and neurons, in special the NPY-IR ones, likely having a compensatory gliogenesis. This supports the correlations between the CTS functional deficits and an anatomical deterioration of its components with the aging process.

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In the central nervous system (CNS) of mammalian, fast synaptic transmission between nerve cells is performed primarily by α-amino-3-hydroxy-5-methyl-4- isoxazolepropionic acid (AMPA) receptors, an ionotropic glutamate receptor that is related with learning, memory and homeostasis of the nervous system. Impairments in their functions are correlated with development of many brain desorders, such as epilepsy, schizophrenia, autism, Parkinson and Alzheimer. The use of willardiine analogs has been shown a powerful tool to understanding of activation and desensitization mechanisms of this receptors, because the modification of a single ligand atom allows the observation of varying levels of efficacy. In this work, taking advantage of Fluorine Willardiine (1.35Å), Hydrogen Willardiine (1.65Å), Bromine Willardiine (1.8Å) and Iodine Willardiine (2.15Å) structures co-crystalized with GluA2 with codes 1MQI, 1MQJ, 1MQH and 1MQG, we attempted to energetically differentiate the four ligands efficacy. The complexes were submitted to energetic calculations based on density functional theory (DFT), under the optics of molecular fractionation with conjugate caps (MFCC) method. Obtained results show a relationship between the energetic values and willardiines efficacy order (FW> HW > BrW > IW), also show the importance of E705, R485, Y450, S654, T655, T480 e P478 as the amino acids that contribute most strongly with the interaction of four partial agonists. Furthermore, we outlined the M708 behaviour, attracted by FW and HW ligands, and repels by BrW and IW. With the datas reported on this work, it is possible for a better understanding of the AMPA receptor, which can serve as an aid in the development of new drugs for this system.

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Anxiety disorders and Parkinson’s disease (PD) affect a large portion of the world population. Indeed, therapeutic alternatives available do not contribute to improve most clinical conditions and/or are linked with undesirable side effects. Thus, there is a great demand for the development of new drugs to treatment of these diseases. Passiflora cincinnata Mast. is a native species present in several Brazilian states, popularly known as “maracujá do mato”, “maracujá tubarão” or “maracujá mochila”. Additionally, species of Passiflora genus are traditionally known for their exotic flowers, edible fruits with pronounced flavor and for their sedative, tranquilizer and anxiolytic properties reported by folk medicine. These plants possess important organic compounds such as phenols, cyanogenic glycosides, flavonoids and alkaloids, which are responsible for the anxiolytic, antioxidant, anti-inflammatory, antihyperglycemic, among others activities when tested in mammals. Despite this fact, only a few studies have been conducted to investigate the possible in vivo biological effects of Passiflora cincinnata Mast extracts. Thereby, in this study we evaluated the effects of the alcoholic extract of this plant in anxiety and PD animal model. Mice acutely or chronically administered with ethanolic extract of P. cincinnata do not showed any anxiogenic- or anxyolitic-like effect in elevated plus maze (EPM). In order to reproduce PD symptom’s in mice, we administered repeated injections of reserpine which progressively induced motor impairments such as increase in catalepsy, oral movements, and reduction of the average speed of the animals in the open field, as well as depleted dopamine prodution in SNpc cells. Furthermore, this treatment resulted in the loss of aversive memory recall in mice when undergoing PMDAT. Yet, passiflora group also show this amnesic profile. However, animals treated concomitantly with the alcoholic extract of Passiflora cincinnata Mast. showed higher latency for the onset of motor impairment evaluated by catalepsy. Thus, our results shows that the alcoholic extract of the plant P. cincinnata was able to delay the onset of the catalepsy induced by reserpine administration, plus reverted the depletion of dopamine production in SNpc cells.

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One of several techniques applied to production processes oil is the artificial lift, using equipment in order to reduce the bottom hole pressure, providing a pressure differential, resulting in a flow increase. The choice of the artificial lift method depends on a detailed analysis of the some factors, such as initial costs of installation, maintenance, and the existing conditions in the producing field. The Electrical Submersible Pumping method (ESP) appears to be quite efficient when the objective is to produce high liquid flow rates in both onshore and offshore environments, in adverse conditions of temperature and in the presence of viscous fluids. By definition, ESP is a method of artificial lift in which a subsurface electric motor transforms electrical into mechanical energy to trigger a centrifugal pump of multiple stages, composed of a rotating impeller (rotor) and a stationary diffuser (stator). The pump converts the mechanical energy of the engine into kinetic energy in the form of velocity, which pushes the fluid to the surface. The objective of this work is to implement the optimization method of the flexible polyhedron, known as Modified Simplex Method (MSM) applied to the study of the influence of the modification of the input and output parameters of the centrifugal pump impeller in the channel of a system ESP. In the use of the optimization method by changing the angular parameters of the pump, the resultant data applied to the simulations allowed to obtain optimized values of the Head (lift height), lossless efficiency and the power with differentiated results.

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The 3-Hidroxytyramine/dopamine (DA) is a monoamine of catecholamine family and isthe precursor substance synthesis of noradrenaline and adrenaline, having the enzymeTyrosine Hydroxylase (TH) as this regulatory process. In addition, the DA has theability to act as a neurotransmitter in the Central Nervous System - SNC, being themain neurotransmitter of brain nuclei, namely of A8 to A16. The nuclei of the midbrainthat express DA are the Retrorubral Field (RRF, A8), the Substantia Nigra parsCompacta (SNc, A9) and the Ventral Tegmental Area (VTA, A10). Such nuclei areinvolved in complex three circuitry that are the mesostriatal, mesolimbic andmesocotical and are directly related with several behavioral manifestations as motricitycontrol, reward signaling in behavioral learning, motivation and pathologicalconditions, such as Parkinson's Disease and schizophrenia. Interestingly, many of themorphological bases of these neural disturbance remain unknown. Considering therelevance of mesencephalic dopaminergic nuclei, the aim of this research is tocharacterize morphologically the dopaminergic nuclei (clusters A8, A9 and A10) of themidbrain of the bat (Artibeus planirostris). The Artibeus planirostris is a common bat inRio Grande do Norte. Ten animals were used in this research. The animals wereanesthetized, perfused, and the brain was removed from the skull. After dehydration insucrose, the brain was underwent microtomy. Saggital and coronal sections wereobtained and collected in six separate series. The series were Nissl-stained to identifythe cytoarchitectonic boundaries and the other series were subjected toimmunohistochemistry for TH. After cytoarchitectonic analysis and TH+ cellsidentification was possible to establish the anatomical boundaries of the nuclei, as wellas the subdivisions of three of the midbrain dopaminergic nuclei. The SNc is the mostrostral nucleus observed in the midbrain and is identified throughout the rostrocaudalextension of the midbrain. The VTA neurons were seen immediately caudal to the SNcappearance. The RRF neurons were observed just in the caudal levels of the midbrain.The SNc in Artibeus planirostris shows a particular feature, the tail of the SNc. The tailhave been described just in two other studied species. The present work shows aparticular variation in the organizational morphology of the SNc in the artibeus andcontribute to understand the phylogenetic routes by which the dopaminergic system hasevolved.