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1.
Brain Struct Funct ; 224(5): 1933-1946, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31089853

RESUMO

The laminar organization of the motor cortex of the sheep and other large domestic herbivores received scarce attention and is generally considered homologous to that of rodents and primates. Thickness of the cortex, subdivision into layers and organization are scarcely known. In the present study, we applied different modern morphological, mathematical and image-analyses techniques to the study of the motor area that controls movements of the forelimb in the sheep. The thickness of the cortex resulted comparable to that of other terrestrial Cetartiodactyls (but thicker than in marine Cetartiodactyls of similar body mass). The laminar organization showed marked development of layer 1, virtual absence of layer 4, and image analysis suggested prevalence of large irregular neural cells in the deeper layers. Diffusion tensor imaging revealed robust projections from the motor cortex to the pyramids in the brainstem, and well evident tracts descending to the tegmentum of the mesencephalon and dorsal pons. Our data contrast the general representation of the motor system of this species, considered to be predominantly based on extra-pyramidal tracts that originate from central pattern generators in the brainstem.


Assuntos
Tronco Encefálico/anatomia & histologia , Tratos Extrapiramidais/anatomia & histologia , Membro Anterior/anatomia & histologia , Córtex Motor/anatomia & histologia , Animais , Mapeamento Encefálico/métodos , Imagem de Tensor de Difusão/métodos , Neurônios/patologia , Ovinos
2.
Anat Rec (Hoboken) ; 302(9): 1638-1646, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30730115

RESUMO

Despite increasing interest in the claustrum (Cl) over the last decades, its function is still a puzzling problem. Among the experimental species of potential use in Cl research, the pig is considered an interesting model, because of the similarities of its brain with the corresponding cortical and subcortical human structures. The swine Cl presents a peculiar morphology, characterized by a wide posterior enlargement, ideal for physiological investigations. There is a wealth of data on general anatomy, cytoarchitecture, and chemo architecture of the Cl, but much less is known about the dendritic morphometry of its neurons. Dendritic length and branching pattern are key features to understand the organization of the microcircuitry, and thus the delineation of the structure-function relationships of the Cl. To this effect, we undertook (a) a quantitative study of the dendrites of the spiny neurons of the swine Cl, employing the Golgi staining; and (b) an immunohistochemical analysis to describe the distribution of the parvalbumin (PV)-immunoreactive interneurons throughout the same nucleus. Taken together, the results that we report here show that the dendritic architecture and the distribution of the PV expressing interneurons change when the Cl of this species changes its shape along the rostro-caudal axis, thus suggesting a potentially specific function for the large posterior puddle. Anat Rec, 302:1638-1646, 2019. © 2019 American Association for Anatomy.

3.
J Exp Biol ; 222(Pt 5)2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30760548

RESUMO

The retia mirabilia are vascular nets composed of small vessels dispersed among numerous veins, allowing blood storage, regulation of flow and pressure damping effects. Here, we investigated their potential role during the diving phase of the bottlenose dolphin (Tursiops truncatus). To this effect, the whole vertebral retia mirabilia of a series of dolphins were removed during post-mortem analysis and examined to assess vessel diameters, and estimate vascular volume and flow rate. We formulated a new hemodynamic model to help clarify vascular dynamics throughout the diving phase, based on the total blood volume of a bottlenose dolphin, and using data available about the perfusion of the main organs and body systems. We computed the minimum blood perfusion necessary to the internal organs, and the stroke volume and cardiac output during the surface state. We then simulated breath-holding conditions and perfusion of the internal organs under the diving-induced bradycardia and reduction of stroke volume and cardiac output, using 10 beats min-1 as the limit for the heart rate for an extended dive of over 3 min. Within these simulated conditions, the retia mirabilia play a vital role as reservoirs of oxygenated blood that permit functional performances and survival of the heart and brain. Our theoretical model, based on the actual blood capacity of the retia mirabilia and available data on organ perfusion, considers the dynamic trend of vasoconstriction during the diving phase and may represent a baseline for future studies on the diving physiology of dolphins and especially for the blood supply to their brain.

4.
Anat Rec (Hoboken) ; 302(7): 1226-1237, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30315632

RESUMO

In this study, we characterized the morphological aspects of the early development of the head of the alpaca (Vicugna pacos) and identified the main structures of the central nervous system during the first trimester of pregnancy. The topography and the cytoarchitecture of the fetal brain regions were described by histological analysis of the brain sections. We performed this analysis on alpaca embryos and fetuses presumably aged 20, 30, 45, and 90 days. For the description of the external body structures we considered the shape of the head, the development of the optic primordium, the dorsal curvature of the body, the limb buds, the umbilical cord and relative vessels, and the thickness and transparency of the skin. The prosencephalic, mesencephalic, and the rhomboencephalic vesicles were described by analyzing sagittal sections of the head. The present article provides the first progressive morphological and anatomical description of alpaca brain during early development. A detailed study represents an important basis to further understand the phases of prenatal development in this species, since information about alpaca embryology in incomplete and reproductive failure is a relevant factor. These data are important also for interspecies comparisons and application of reproductive biotechnologies. Anat Rec, 302:1226-1237, 2019. © 2018 Wiley Periodicals, Inc.

5.
J Comp Neurol ; 526(17): 2898-2917, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30255945

RESUMO

In an effort to systematically describe the neurochemical anatomy of the bovine anterior hypothalamus, we used a series of immunocytochemical markers such as acetylcholine esterase (AChE), arginine-vasopressin (AVP), calbindin (Calb), galanin (Gal), neuropeptide-Y (NPY), oxytocin (OXT), somatostatin (SST), and vasoactive intestinal peptide (VIP). We also investigated the potential sex difference present in the suprachiasmatic nucleus (SCN) and the vasopressin-oxytocin containing nucleus (VON) of six male and six female Bos taurus. Our study revealed that the cytochemical structure of the cattle anterior hypothalamus follows the blueprint of other mammals. The VON, which was never described before in cattle, showed a sex difference with a 33.7% smaller volume and 23.2% fewer magnocellular neurons (approximately 20-30 µm) in the male. The SCN also did show a sex difference in VIP neurons and volume with a 36.1% larger female nucleus with 28.1% more cells. Additionally, we included five heifers with freemartin syndrome as a new animal model relevant to sexual differentiation in the brain. This is, to the best of our knowledge, the first freemartin study in relation to the brain. Surprisingly, the SCN of freemartin heifers was 32.5% larger than its control male and female counterparts with 29% more VIP cells. Conversely, the freemartin VON had an intermediary size between male and female. To analyze our data, a classical statistical analysis and a novel multivariate and multi-aspect approach were applied. These findings shed new light on sexual dimorphism in the bovine brain and present this species with freemartins as a valuable animal model in neuroscience.


Assuntos
Hipotálamo Anterior/fisiologia , Ocitocina/metabolismo , Diferenciação Sexual/fisiologia , Vasopressinas/metabolismo , Animais , Bovinos , Contagem de Células , Feminino , Freemartinismo/patologia , Hipotálamo Anterior/citologia , Hipotálamo Anterior/metabolismo , Masculino , Neurônios/fisiologia , Neuropeptídeos/análise , Neuropeptídeos/metabolismo , Caracteres Sexuais , Núcleo Supraquiasmático/citologia , Núcleo Supraquiasmático/fisiologia
6.
Sci Rep ; 8(1): 11577, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30068967

RESUMO

Mass strandings of sperm whales (Physeter macrocephalus) are rare in the Mediterranean Sea. Nevertheless, in 2014 a pod of 7 specimens stranded alive along the Italian coast of the Central Adriatic Sea: 3 individuals died on the beach after a few hours due to internal damages induced by prolonged recumbency; the remaining 4 whales were refloated after great efforts. All the dead animals were genetically related females; one was pregnant. All the animals were infected by dolphin morbillivirus (DMV) and the pregnant whale was also affected by a severe nephropathy due to a large kidney stone. Other analyses ruled out other possible relevant factors related to weather conditions or human activities. The results of multidisciplinary post-mortem analyses revealed that the 7 sperm whales entered the Adriatic Sea encountering adverse weather conditions and then kept heading northward following the pregnant but sick leader of the pod, thereby reaching the stranding site. DMV infection most likely played a crucial role in impairing the health condition and orientation abilities of the whales. They did not steer back towards deeper waters, but eventually stranded along the Central Adriatic Sea coastline, a real trap for sperm whales.


Assuntos
Comportamento Animal , Infecções por Morbillivirus/veterinária , Morbillivirus/isolamento & purificação , Cachalote , Animais , Itália , Mar Mediterrâneo , Infecções por Morbillivirus/patologia
7.
Front Neurosci ; 12: 497, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30079011

RESUMO

Pre-clinical research is carried out on animal models, mostly laboratory rodents, with the ultimate aim of translating the acquired knowledge to humans. In the last decades, adult neurogenesis (AN) has been intensively studied since it is viewed as a tool for fostering brain plasticity, possibly repair. Yet, occurrence, location, and rate of AN vary among mammals: the capability for constitutive neuronal production is substantially reduced when comparing small-brained, short living (laboratory rodents) and large-brained, long-living species (humans, dolphins). Several difficulties concerning scarce availability of fresh tissues, technical limits and ethical concerns did contribute in delaying and diverting the achievement of the picture of neurogenic plasticity in large-brained mammals. Some reports appeared in the last few years, starting to shed more light on this issue. Despite technical limits, data from recent studies mostly converge to indicate that neurogenesis is vestigial, or possibly absent, in regions of the adult human brain where in rodents neuronal addition continues into adult life. Analyses carried out in dolphins, mammals devoid of olfaction, but descendant of ancestors provided with olfaction, has shown disappearance of neurogenesis in both neonatal and adult individuals. Heterogeneity in mammalian structural plasticity remains largely underestimated by scientists focusing their research in rodents. Comparative studies are the key to understand the function of AN and the possible translational significance of neuronal replacement in humans. Here, we summarize comparative studies on AN and discuss the evolutionary implications of variations on the recruitment of new neurons in different regions and different species.

8.
Animals (Basel) ; 8(9)2018 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-30134557

RESUMO

No data have been published on the use of infrared thermography (IRT) to evaluate sheep emotions. We assessed whether this technique can be used as a non-invasive measure of negative emotions. Two voluntary animal approach (VAA) tests were conducted (and filmed) on five ewes before and after being restrained. The restraining process was performed by a handler for five minutes. IRT was used during restraint and the VAA tests. The lacrimal caruncle temperature was significantly higher during restraint and in the VAA test after the restraint compared with the VAA test before the restraint (Wilcoxon's test; p = 0.04). The latency period until first contact was longer in the second VAA test (132 s) than in the first one (60 s). Our preliminary results suggest that IRT, combined with behavioral data, is a non-invasive technique that can be useful to assess stress and infer about negative emotions in sheep.

9.
Forensic Sci Int ; 290: e19-e23, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30025595

RESUMO

Fishing activities are considered one of the most relevant threats for cetaceans and sea turtles conservation since these animals are sometimes found dead entangled in fishing gears. Currently, postmortem diagnosis is based mainly on the presence of nets and lines on the body and the related marks and injuries evident at gross examination. A more detailed and objective evidence is needed to clarify doubts cases and the diatoms technique, used in forensic human medicine, could support drowning diagnosis also in this field. Diatoms' investigation was implemented to be applied in marine vertebrate on 8 striped (Stenella coeruleoalba) and 1 bottlenose (Tursiops truncatus) dolphins and 5 sea turtles (Caretta caretta) stranded along the Italian coastlines with a likely cause of death hypothized on necropsies carried out by veterinary pathologists. Diatoms were microscopically searched in the bone marrow collected from long bones implementing protocols used in human medicine and their presence was observed in 4 cetaceans and 2 sea turtles. Despite a clear relation between diatoms' presence and amount and the likely cause of death was not proved due to the poor number of samples, the higher burden of diatoms was found in 3 animals deemed to be death for the interaction with human activity. Despite more studied are necessary to identify the possible relation between the cause of death and diatoms' findings, the present study implemented this technique to be adapted to marine animals, confirming its possible application also in veterinary forensic medicine.


Assuntos
Medula Óssea/patologia , Golfinho Nariz-de-Garrafa , Diatomáceas/isolamento & purificação , Afogamento/diagnóstico , Stenella , Tartarugas , Animais , Conservação dos Recursos Naturais , Afogamento/veterinária , Ciências Forenses , Projetos Piloto
10.
R Soc Open Sci ; 5(4): 171645, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29765640

RESUMO

The rigid structure of the mammalian trachea is functional to maintain constant patency and airflow during breathing, but no gas exchange takes place through its walls. The structure of the organ in dolphins shows increased rigidity of the tracheal cartilaginous rings and the presence of vascular lacunae in the submucosa. However, no actual comparison was ever made between the size and capacity of the vascular lacunae of the dolphin trachea and the potentially homologous structures of terrestrial mammals. In the present study, the extension of the lacunae has been compared between the bottlenose dolphin and the bovine, a closely related terrestrial Cetartiodactyla. Our results indicate that the extension of the blood spaces in the submucosa of dolphins is over 12 times larger than in the corresponding structure of the bovines. Furthermore, a microscopic analysis revealed the presence of valve-like structures in the walls of the cetacean lacunae. The huge difference in size suggests that the lacunae are not merely a product of individual physiological plasticity, but may constitute a true adaptive evolutionary character, functional to life in the aquatic environment. The presence of valve-like structures may be related to the regulation of blood flow, and curtail excessive compression under baric stress at depth.

11.
Sci Rep ; 8(1): 5486, 2018 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-29615733

RESUMO

The locus coeruleus (LC) is the largest catecholaminergic nucleus and extensively projects to widespread areas of the brain and spinal cord. The LC is the largest source of noradrenaline in the brain. To date, the only examined Delphinidae species for the LC has been a bottlenose dolphin (Tursiops truncatus). In our experimental series including different Delphinidae species, the LC was composed of five subdivisions: A6d, A6v, A7, A5, and A4. The examined animals had the A4 subdivision, which had not been previously described in the only Delphinidae in which this nucleus was investigated. Moreover, the neurons had a large amount of neuromelanin in the interior of their perikarya, making this nucleus highly similar to that of humans and non-human primates. This report also presents the first description of neuromelanin in the cetaceans' LC complex, as well as in the cetaceans' brain.


Assuntos
Golfinhos , Locus Cerúleo/metabolismo , Animais , Locus Cerúleo/citologia , Melaninas/metabolismo , Neurônios/enzimologia , Tirosina 3-Mono-Oxigenase/metabolismo
12.
J Anat ; 232(1): 158-166, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28967096

RESUMO

Over the past decades, the number of studies employing the pig brain as a model for neurochemical studies has dramatically increased. The key translational features of the pig brain are the similarities with the cortical and subcortical structures of the human brain. In addition, the caudalmost part of the pig claustrum (CL) is characterized by a wide enlargement called posterior puddle, an ideal structure for physiological recordings. Several hypotheses have been proposed for CL function, the key factor being its reciprocal connectivity with most areas of the cerebral cortex and selected subcortical structures. However, afferents from the brainstem could also be involved. The brainstem is the main source of catecholaminergic axons that play an important neuromodulatory action in different brain functions. To study a possible role of the CL in catecholaminergic pathways, we analyzed the presence and the distribution of afferents immunostained with antibodies against tyrosine hydroxylase (TH) and dopamine betahydroxylase (DBH) in the pig CL. Here we show that the CL contains significant TH immunoreactive axons contacting perikarya, whereas projections staining for DBH are very scarce. Our findings hint at the possibility that brainstem catecholaminergic afferents project to the CL, suggesting (i) a possible role of this nucleus in functions controlled by brainstem structures; and, consequently, (ii) its potential involvement in the pathophysiology of neurodegenerative pathologies, including Parkinson's disease (PD).


Assuntos
Neurônios Adrenérgicos/enzimologia , Gânglios da Base/citologia , Vias Neurais/citologia , Animais , Suínos
13.
Brain Behav Evol ; 90(3): 193-210, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28768268

RESUMO

The present study focuses on the relationship between neocortical structures and functional aspects in three selected mammalian species. Our aim was to compare cortical layering and neuron density in the projection areas (somatomotor, M1; somatosensory, S1; auditory, A1; and visual, V1; each in a wider sense). Morphological and design-based stereological analysis was performed in the wild boar (Sus scrofa scrofa) as a representative terrestrial hoofed animal (artiodactyl) and the common dolphin (Delphinus delphis) as a highly derived related aquatic mammal (cetartiodactyl). For comparison, we included the human (Homo sapiens) as a well-documented anthropoid primate. In the cortex of many mammals, layer IV (inner granular layer) is the main target of specific thalamocortical inputs while layers III and V are the main origins of neocortical projections. Because the fourth layer is indistinct or mostly lacking in the primary neocortex of the wild boar and dolphins, respectively, we analyzed the adjacent layers III and V in these animals. In the human, all the three layers were investigated separately. The stereological data show comparatively low neuron densities in all areas of the wild boar and high cell counts in the human (as expected), particularly in the primary visual cortex. The common dolphin, in general, holds an intermediate position in terms of neuron density but exhibits higher values than the human in a few layers. With respect to the situation in the wild boar, stereological neuron counts in the dolphin are consistently higher, with a maximum in layer III of the visual cortex. The extended auditory neocortical field in dolphins and the hypertrophic auditory pathway indicate secondary neurobiological adaptations to their aquatic habitat during evolution. The wild boar, however, an omnivorous quadruped terrestrial mammal, shows striking specializations as to the sensorimotor neurobiology of the snout region.


Assuntos
Neocórtex/anatomia & histologia , Neocórtex/citologia , Adaptação Fisiológica , Animais , Córtex Auditivo/anatomia & histologia , Vias Auditivas/anatomia & histologia , Vias Auditivas/fisiologia , Contagem de Células , Golfinhos Comuns/anatomia & histologia , Humanos/anatomia & histologia , Mamíferos/anatomia & histologia , Neurônios/fisiologia , Especificidade da Espécie , Sus scrofa/anatomia & histologia , Córtex Visual/anatomia & histologia
15.
Anat Rec (Hoboken) ; 300(8): 1502-1511, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28346748

RESUMO

The anatomy of the giraffe (Giraffa camelopardalis Linnaeus, 1758) has been poorly studied, except for the circulatory system. In particular, only a handful of studies have concerned the brain of this species since the first description in 1839. Accordingly, only a very few articles discussing encephalization mentioned the giraffe or used it in their calculations. In this article, we performed a thorough examination of the literature including old and grey, regarding the central nervous system of the giraffe. Furthermore, we examined the brain of 3 giraffes, and calculated the encephalization quotient (EQ) of the species, based on our own data and the values found in the literature. We also revised the pre-existing literature and re-mapped the main sulci based on current comparative interpretation and anatomical nomenclature. Our results were compared to those of other selected significant mammals. The mean brain weight was of 719.9 ± 12.5 g. Our data indicate that the EQ of the giraffe is 0.64 and matches that of the typical ungulate, despite having the largest brain among terrestrial Cetartiodactyla. This emphasizes that the giraffe is a highly specialized mammal, within the limitations of its clad. Anat Rec, 300:1502-1511, 2017. © 2017 Wiley Periodicals, Inc.


Assuntos
Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Girafas/anatomia & histologia , Girafas/fisiologia , Animais , Feminino , Masculino , Neuroanatomia , Literatura de Revisão como Assunto
16.
Front Vet Sci ; 4: 14, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28261586

RESUMO

The present article examines over 63,000 medical records belonging to the Veterinary Hospitals of the Universities of Bologna, Torino, and Padova, all in Northern Italy, and relative to dogs (approximately 50,000), cats (approximately 12,000), and companion horses (slightly less than 1,000). The animals of the three species were divided into age classes and categorized per sex into males, females, and neutered individuals. The mean age at visit and the effects of age classes and category (analyzed via ANOVA) are presented and discussed. The data indicate that many animals are presented to the hospitals either in the early phases of their life (presumably for vaccination and, in cats and dogs, gonadectomy) or in the advanced age (over 10 years in dogs, over 15 years in cats, and over 17 years in horses). The records of very old individuals of the three species are also reported. On the whole, the results suggest that a growing population of mature to old domestic carnivores or companion horses reaches ages that were considered exceptional only a few years ago. The data also testify an evolution in the animal-owner relationship and a renewed respect for the value of life in companion domestic mammals.

17.
Brain Struct Funct ; 222(6): 2743-2757, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28210850

RESUMO

The architecture of the neocortex classically consists of six layers, based on cytological criteria and on the layout of intra/interlaminar connections. Yet, the comparison of cortical cytoarchitectonic features across different species proves overwhelmingly difficult, due to the lack of a reliable model to analyze the connection patterns of neuronal ensembles forming the different layers. We first defined a set of suitable morphometric cell features, obtained in digitized Nissl-stained sections of the motor cortex of the horse, chimpanzee, and crab-eating macaque. We then modeled them using a quite general non-parametric data representation model, showing that the assessment of neuronal cell complexity (i.e., how a given cell differs from its neighbors) can be performed using a suitable measure of statistical dispersion such as the mean absolute deviation-mean absolute deviation (MAD). Along with the non-parametric combination and permutation methodology, application of MAD allowed not only to estimate, but also to compare and rank the motor cortical complexity across different species. As to the instances presented in this paper, we show that the pyramidal layers of the motor cortex of the horse are far more irregular than those of primates. This feature could be related to the different organizations of the motor system in monodactylous mammals.


Assuntos
Cavalos/anatomia & histologia , Macaca fascicularis/anatomia & histologia , Córtex Motor/citologia , Neurônios/citologia , Pan troglodytes/anatomia & histologia , Animais , Proteínas de Ligação ao Cálcio/análise , Forma Celular , Tamanho Celular , Feminino , Processamento de Imagem Assistida por Computador , Imuno-Histoquímica , Masculino , Modelos Estatísticos , Córtex Motor/química , Proteínas do Tecido Nervoso/análise , Neurônios/química , Fenótipo , Análise de Célula Única , Especificidade da Espécie , Coloração e Rotulagem
18.
Brain Struct Funct ; 222(6): 2625-2639, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28238073

RESUMO

Adult neurogenesis has been implicated in brain plasticity and brain repair. In mammals, it is mostly restricted to specific brain regions and specific physiological functions. The function and evolutionary history of mammalian adult neurogenesis has been elusive so far. The largest neurogenic site in mammals (subventricular zone, SVZ) generates neurons destined to populate the olfactory bulb. The SVZ neurogenic activity appears to be related to the dependence of the species on olfaction since it occurs at high rates throughout life in animals strongly dependent on this function for their survival. Indeed, it dramatically decreases in humans, who do not depend so much on it. This study investigates whether the SVZ neurogenic site exists in mammals devoid of olfaction and olfactory brain structures, such as dolphins. Our results demonstate that a small SVZ-like region persists in these aquatic mammals. However, this region seems to have lost its neurogenic capabilities since neonatal stages. In addition, instead of the typical newly generated neuroblasts, some mature neurons were observed in the dolphin SVZ. Since cetaceans evolved from terrestrial ancestors, non-neurogenic SVZ may indicate extinction of adult neurogenesis in the absence of olfactory function, with the retention of an SVZ-like anatomical region either vestigial or of still unknown role.


Assuntos
Golfinhos/fisiologia , Ventrículos Laterais/fisiologia , Neurogênese , Plasticidade Neuronal , Neurônios/fisiologia , Fatores Etários , Animais , Animais Recém-Nascidos , Evolução Biológica , Biomarcadores/análise , Feminino , Ventrículos Laterais/química , Ventrículos Laterais/citologia , Masculino , Neurônios/química , Fenótipo , Olfato , Especificidade da Espécie
19.
Neuroendocrinology ; 104(1): 51-71, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-26882349

RESUMO

In the mammalian brain, the differentiation of neural cells and the developmental organization of the underlying circuitry are influenced by steroid hormones. The estrogen 17-ß estradiol (E2) is one of the most potent regulators of neural growth during prenatal life, synthetized locally from steroid precursors including prenatal testicular testosterone. Estradiol promotes brain differentiation counting sexually dimorphic neural circuits by binding to the estrogen receptors, ER-α and ER-ß. The cerebellum has been described as a site of estrogen action and a potentially sexually dimorphic area. The goal of this study was to analyze the capacity of E2 to affect the growth of male and female fetal bovine cerebellar granule. We performed primary cultures of fetal cerebellar granules, and verified the mRNA expression of the ER-α and ER-ß in both sexes. Moreover, the distribution of ERs in the male and female cerebellar granules of the second fetal stage was characterized by immunohistochemistry. We measured morphological parameters in presence (or absence) of estradiol administration, focusing on the variations of the dendritic branching pattern of granule neurons. By using the nonparametric combination and permutation testing approach, we proposed a sophisticated multivariate statistical analysis to demonstrate that E2 induces multifarious and dimorphic changes in the granule cells. E2 exerts trophic effects in both female and male granules and this effect is stronger in female. Male granules treated with E2 became similar to female control granule. Bos taurus species has a long gestation and a large brain that offers an interesting alternative in comparative neuroscience.


Assuntos
Cerebelo/citologia , Estradiol/farmacologia , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/metabolismo , Neurônios/efeitos dos fármacos , Caracteres Sexuais , Análise de Variância , Animais , Bovinos , Células Cultivadas , Embrião de Mamíferos , Receptor alfa de Estrogênio/genética , Receptor beta de Estrogênio/genética , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Masculino , RNA Mensageiro , Estatísticas não Paramétricas , Tubulina (Proteína)/metabolismo
20.
PLoS One ; 11(6): e0158129, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27336480

RESUMO

The mitochondrion is the power plant of the eukaryotic cell, and tRNAs are the fundamental components of its translational machinery. In the present paper, the evolution of mitochondrial tRNAs was investigated in the Cetacea, a clade of Cetartiodactyla that retuned to water and thus had to adapt its metabolism to a different medium than that of its mainland ancestors. Our analysis focussed on identifying the factors that influenced the evolution of Cetacea tRNA double-helix elements, which play a pivotal role in the formation of the secondary and tertiary structures of each tRNA and consequently manipulate the whole translation machinery of the mitochondrion. Our analyses showed that the substitution pathways in the stems of different tRNAs were influenced by various factors, determining a molecular evolution that was unique to each of the 22 tRNAs. Our data suggested that the composition, AT-skew, and GC-skew of the tRNA stems were the main factors influencing the substitution process. In particular, the range of variation and the fluctuation of these parameters affected the fate of single tRNAs. Strong heterogeneity was observed among the different species of Cetacea. Finally, it appears that the evolution of mitochondrial tRNAs was also shaped by the environments in which the Cetacean taxa differentiated. This latter effect was particularly evident in toothed whales that either live in freshwater or are deep divers.


Assuntos
Adaptação Biológica , Cetáceos/genética , Evolução Molecular , Genes Mitocondriais , RNA de Transferência/genética , Animais , Cetáceos/classificação , Códon , Biologia Computacional/métodos , DNA Mitocondrial , Perfilação da Expressão Gênica , Variação Genética , Genoma Mitocondrial , Conformação de Ácido Nucleico , Filogenia , RNA de Transferência/química , RNA de Transferência/classificação , Análise de Sequência de DNA , Especificidade da Espécie
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