RESUMEN
Recent studies have begun to reveal surprising levels of cell diversity in the human brain, both in adults and during development. Distinctive cellular phenotypes point to complex molecular profiles, cellular hierarchies and signaling pathways in neural stem cells, progenitor cells, neuronal and glial cells. Several recent reports have suggested that neural stem and progenitor cell types found in the developing and adult brain share several properties and phenotypes with cells from brain primary tumors, such as gliomas. This transcriptomic crosstalk may help us to better understand the cell hierarchies and signaling pathways in both gliomas and the normal brain, and, by clarifying the phenotypes of cells at the origin of the tumor, to therapeutically address their most relevant signaling pathways.
Asunto(s)
Neoplasias Encefálicas/genética , Perfilación de la Expresión Génica/métodos , Redes Reguladoras de Genes , Glioma/genética , Células-Madre Neurales/química , Neoplasias Encefálicas/patología , Comunicación Celular , Regulación Neoplásica de la Expresión Génica , Glioma/patología , Humanos , Células Madre Neoplásicas/química , Células Madre Neoplásicas/patología , Fenotipo , Transducción de Señal , Telencéfalo/química , Telencéfalo/citología , Telencéfalo/patologíaRESUMEN
Individual stress coping style (reactive, intermediate and proactive) was determined in 3 groups of 120 pit tagged European seabass using the hypoxia avoidance test. The same three groups (no change in social composition) were then reared according to the standards recommended for this species. Then, 127 days later, individuals initially characterized as reactive, intermediate or proactive were submitted to an acute confinement stress for 30 min. Blood samples were taken to measure plasma cortisol levels 30 min (Stress30) or 150 min (Stress150) after the end of the confinement stress. Individuals were then sacrificed to sample the telencephalon in order to measure the main monoamines and their catabolites (at Stress30 only). Individuals from Stress150 were sampled for whole brain for a transcriptomic analysis. The main results showed that reactive individuals had a lower body mass than intermediate individuals which did not differ from proactive individuals. The physiological cortisol response did not differ between coping style at Stress30 but at Stress150 when intermediate and proactive individuals had recovered pre stress levels, reactive individuals showed a significant higher level illustrating a modulation of stress recovery by coping style. Serotonin turnover ratio was higher in proactive and reactive individuals compared to intermediate individuals and a significant positive correlation was observed with cortisol levels whatever the coping style. Further, the confinement stress led to a general increase in the serotonin turnover comparable between coping styles. Stress150 had a significant effect on target mRNA copy number (Gapdh mRNA copy number decreased while ifrd1 mRNA copy number increased) and such changes tended to depend upon coping style.
Asunto(s)
Adaptación Psicológica/fisiología , Lubina/fisiología , Estrés Psicológico/fisiopatología , Ácido 3,4-Dihidroxifenilacético/análisis , Animales , Espacios Confinados , Dopamina/análisis , Femenino , Hidrocortisona/sangre , Ácido Hidroxiindolacético/análisis , Masculino , Norepinefrina/análisis , Serotonina/análisis , Telencéfalo/química , Telencéfalo/metabolismo , Transcriptoma/fisiologíaRESUMEN
Ventralization, a major patterning process in the developing vertebrate neural tube (central nervous system, CNS), depends on Sonic hedgehog (SHH) as a main signaling morphogen. We studied the CNS of late larval and young adult zebrafish in a transgenic shh-GFP line revealing increased neuroanatomical detail due to the progressed differentiation state compared to earlier stages. Some major findings emerge from the present study. (a) shh -GFP is still expressed along the adult zebrafish CNS neuraxis in most locations seen in larvae. (b) We newly identify a ventroposterior shh pallidal domain representing the basal telencephalic signaling center important for basal ganglia development known in other vertebrates (i.e., the anterior entopeduncular area-basal medial ganglionic eminence of mammals). (c) We further show late-emerging shh-GFP positive radial glia cells in the medial zone of the dorsal telencephalon (i.e., the teleostan pallial amygdala). (d) Immunostains for tyrosine hydroxylase demonstrate that there is selective colocalization in adult dopamine cells with shh-GFP in the posterior tuberculum, including in projection cells to striatum, which represents a striking parallel to amniote mesodiencephalic dopamine cell origin from shh expressing floor plate cells. (e) There is no colocalization of shh and islet1 as shown by respective shh-GFP and islet1-GFP lines. (f) The only radially far migrated shh-GFP cells are located in the preglomerular area. (g) There are no adult cerebellar and tectal shh-GFP cells confirming their exclusive role during early development as previously reported by our laboratory.
Asunto(s)
Neuronas Dopaminérgicas/metabolismo , Globo Pálido/metabolismo , Proteínas Hedgehog/biosíntesis , Prosencéfalo/metabolismo , Telencéfalo/metabolismo , Proteínas de Pez Cebra/biosíntesis , Animales , Animales Modificados Genéticamente , Neuronas Dopaminérgicas/química , Expresión Génica , Globo Pálido/química , Proteínas Hedgehog/análisis , Proteínas Hedgehog/genética , Prosencéfalo/química , Transducción de Señal/fisiología , Telencéfalo/química , Pez Cebra , Proteínas de Pez Cebra/análisis , Proteínas de Pez Cebra/genéticaRESUMEN
INTRODUCTION: Proteasome regulates proteostasis, and can be compromised in neurodegenerative diseases. Thus, our aim was to correlate the activity of proteasome to the level of polyphenols in telencephalon during murine adulthood. METHODS: Proteasome activity, polyphenols and other variables (glucose and hydroperoxides) were analysed in Balb/c female telencephala (n = 20, age = 4-12 months), using multivariate methods. RESULTS: The following values were found: proteasome activity = 3.1 ± 0.6 FI/µg of tissue proteins, glucose = 0.1 ± 0.0 µg/µg, hydroperoxides = 363.4 ± 96.6 OD/µg, and polyphenols = 0.1 ± 0.0 ng/µg. Polyphenols reduced during aging showed a direct correlation with proteasome (Pearson's coefficient = 0.43, p = 0.0590, and a multivariate linear regressive coefficient = 17.85, p = 0.0216), with glucose and hydroperoxides being not involved (p>0.1). This correlation was confirmed by partial least square regression (beta = 0.67). CONCLUSION: Proteasome activity can be affected during ageing, and promoted by telencephalic polyphenol levels. Thus, these diet compounds might exert benefits in adult brain.
Asunto(s)
Glucosa/análisis , Peróxido de Hidrógeno/análisis , Polifenoles/análisis , Complejo de la Endopetidasa Proteasomal/análisis , Telencéfalo/química , Animales , Peso Corporal , Femenino , Glucosa/metabolismo , Peróxido de Hidrógeno/metabolismo , Ratones , Ratones Endogámicos BALB C , Polifenoles/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismoRESUMEN
Injury-activated endogenous neural stem cells (NSCs) in the spinal cord have promising therapeutic applications for rebuilding the neuronal relays after spinal cord injury (SCI) because of their lack of immune-rejection following exogenous cell transplantation. However, these NSCs rarely differentiate into neurons and the damaged axonal regenerative ability is drastically reduced due to the adverse SCI microenvironment. Cetuximab, an EGFR signaling antagonist, has demonstrated the ability of promoting NSC differentiation into neurons. Taxol, in addition to stabilizing microtubules, has shown potential for enhancing axonal regeneration and reducing scar formation after SCI. In this study, we further verified the combined therapeutic effects of Cetuximab and Taxol on inhibition of scar deposition and promotion of neuronal differentiation, axonal outgrowth and functional recovery in a rat severe SCI model. A linear orderly collagen scaffold modified with Cetuximab and Taxol was grafted into the SCI site after the complete removal of 4 mm of spinal tissue. The results showed that the combined functional scaffold implantation significantly increased neural regeneration to reconnect the neural network. Moreover, scaffold transplantation decreases the deposition of varied scar-related inhibitors within the lesion center, further reflecting the need for a combination dedicated to increasing motor function following SCI. Collagen scaffold based-combined therapy provides a potential strategy for improving functional restoration of the injured spinal cord.
Asunto(s)
Cetuximab/farmacología , Proteínas de la Mielina/farmacología , Fármacos Neuroprotectores/farmacología , Paclitaxel/farmacología , Traumatismos de la Médula Espinal/tratamiento farmacológico , Andamios del Tejido , Animales , Diferenciación Celular/efectos de los fármacos , Cicatriz/prevención & control , Colágeno/química , Sinergismo Farmacológico , Quimioterapia Combinada , Femenino , Proteínas de la Mielina/aislamiento & purificación , Regeneración Nerviosa/efectos de los fármacos , Células-Madre Neurales/citología , Células-Madre Neurales/efectos de los fármacos , Células-Madre Neurales/metabolismo , Plasticidad Neuronal/efectos de los fármacos , Neuronas/citología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Cultivo Primario de Células , Ratas , Ratas Sprague-Dawley , Médula Espinal/efectos de los fármacos , Médula Espinal/metabolismo , Médula Espinal/patología , Traumatismos de la Médula Espinal/metabolismo , Traumatismos de la Médula Espinal/patología , Telencéfalo/químicaRESUMEN
The neocortex plays a key role in cognition, volitional motor control and sensory perception and has undergone tremendous expansion during evolution. The mature neocortex consists of radially aligned neurons that are arranged in six layers. Layers II-VI are often split into two groups: deep and upper layers, both building up the so-called cortical plate during embryonic and foetal development. So far cortical neurogenesis, including the generation of deep and upper layers, has mostly been studied in laboratory rodents and primates. However, precise data for most companion animals are lacking. This study determined the main period of neurogenesis, specifically the timing of deep and upper layer generation, in the developing domestic cat, pig and sheep neocortex using immunohistochemistry for specific neuronal markers, that is Tbr1 and Brn2. We found that the general sequence of neural events is preserved among cat, pig, sheep and other mammalian species. However, we observed differences in the timing of the overall cortical neurogenic period and occurrence of distinct neural events when these three species were compared. Moreover, our data provide further evidence that the cortical neurogenic period and gestation length might be tightly related. Together, these data expand our current understanding of neocortex development and are important for future studies investigating neocortex development and expansion especially in companion animals.
Asunto(s)
Gatos/embriología , Neocórtex/embriología , Ovinos/embriología , Porcinos/embriología , Animales , Gatos/crecimiento & desarrollo , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Inmunohistoquímica/veterinaria , Modelos Lineales , Microscopía Confocal/veterinaria , Neocórtex/química , Neocórtex/crecimiento & desarrollo , Neocórtex/metabolismo , Ovinos/crecimiento & desarrollo , Estadística como Asunto , Porcinos/crecimiento & desarrollo , Proteínas de Dominio T Box/genética , Proteínas de Dominio T Box/metabolismo , Telencéfalo/químicaRESUMEN
By filtering relevant sensory inputs and initiating stress responses, the brain is an essential organ in stress coping and adaptation. However, exposure to chronic or repeated stress can lead to allostatic overload, where neuroendocrinal and behavioral reactions to stress become maladaptive. This work examines forebrain mechanisms involved in allostatic processes in teleost fishes. Plasma cortisol, forebrain serotonergic (5-HTergic) neurochemistry, and mRNA levels of corticotropin-releasing factor (CRF), CRF-binding protein (CRF-BP), CRF receptors (CRFR1 and CRFR2), mineralocorticoid receptor (MR), glucocorticoid receptors (GR1 and GR2) and serotonin type 1A (5-HT1A) receptors (5-HT1Aα and 5-HT1Aß) were investigated at 1â h before and 0, 1 and 4â h after acute stress, in two groups of rainbow trout held in densities of 25 and 140â kgâ m-3 for 28â days. Generally, being held at 140â kgâ m-3 resulted in a less pronounced cortisol response. This effect was also reflected in lower forebrain 5-HTergic turnover, but not in mRNA levels in any of the investigated genes. This lends further support to reports that allostatic load causes fish to be incapable of mounting a proper cortisol response to an acute stressor, and suggests that changes in forebrain 5-HT metabolism are involved in allostatic processes in fish. Independent of rearing densities, mRNA levels of 5-HT1Aα and MR were downregulated 4â h post-stress compared with values 1â h post-stress, suggesting that these receptors are under feedback control and take part in the downregulation of the hypothalamic-pituitary-interrenal (HPI) axis after exposure to an acute stressor.
Asunto(s)
Regulación de la Expresión Génica , Oncorhynchus mykiss/genética , Oncorhynchus mykiss/fisiología , Estrés Fisiológico/genética , Telencéfalo/química , Telencéfalo/metabolismo , Animales , Hidrocortisona/sangre , Neuroquímica , Oncorhynchus mykiss/sangre , Reacción en Cadena en Tiempo Real de la Polimerasa , Serotonina/metabolismoRESUMEN
Estrogens are not only critical for sexual differentiation it is well-known for the role of 17ß-estradiol (E2) in the adult brain modulating memory, learning, mood and acts as a neuroprotector. E2 exerts its actions through two classical receptors: estrogen receptor alpha (ERα) and estrogen receptor beta (ERß). The distribution of both receptors changes from one brain area to another, E2 being able to modulate their expression. Among the classical features of aging in humans, we find cognitive impairment, dementia, memory loss, etc. As estrogen levels change with age, especially in females, it is important to know the effects of low E2 levels on ERα distribution; results from previous studies are controversial regarding this issue. In the present work, we have studied the effects of long-term E2 depletion as well as the ones of E2 treatment on ERα brain distribution of ovariectomized rats along aging in the diencephalon and in the telencephalon. We have found that ovariectomy causes downregulation and affects subcellular localization of ERα expression during aging, meanwhile prolonged estrogen treatment produces upregulation and overexpression of the receptor levels. Our results support the idea of the region-specific neuroprotection mechanisms mediated by estradiol.
Asunto(s)
Envejecimiento/metabolismo , Química Encefálica/fisiología , Encéfalo/metabolismo , Estradiol/farmacología , Receptor alfa de Estrógeno/metabolismo , Terapia de Reemplazo de Hormonas , Espacio Intracelular/metabolismo , Envejecimiento/efectos de los fármacos , Animales , Encéfalo/citología , Encéfalo/efectos de los fármacos , Corteza Cerebral/química , Corteza Cerebral/citología , Densitometría , Diencéfalo/química , Diencéfalo/citología , Diencéfalo/efectos de los fármacos , Estrógenos/farmacología , Femenino , Inmunohistoquímica , Espacio Intracelular/efectos de los fármacos , Ratas , Ratas Wistar , Telencéfalo/química , Telencéfalo/citología , Telencéfalo/efectos de los fármacosRESUMEN
Leucine-rich glioma inactivated 1 (Lgi1) is a secreted synaptic protein that organizes a transsynaptic protein complex throughout the brain. Mutations in the Lgi1 gene have been found in patients with autosomal dominant lateral temporal lobe epilepsy (ADLTE). Although a large number of studies have focused on the expression and function of Lgi1 in the postnatal brain, information regarding its functions and distribution during development remains sparse. Here we report that Lgi1 mRNA is preferentially expressed in the caudal ganglionic eminence (CGE) of the early embryonic telencephalon, and LGI1 protein is unexpectedly localized in the nucleus of dissociated CGE neurons. Using bioinformatics analysis, we found that LGI1 contains a putative nuclear localization signal (NLS) in its leucine-rich repeat C-terminal domain. Furthermore, we show that the transient expression of Lgi1 in CGE neurons resulted in nuclear translocation of the LGI1 protein, and a mutation in the NLS led to the retention of LGI1 in the cytoplasm. We also confirmed that the NLS sequence of LGI1 had the ability to mediate the nuclear localization by using the NLS-containing fusion protein. Interestingly, when Lgi1 was expressed in neurons obtained from the medial ganglionic eminence or cerebral cortex, almost no nuclear localization of LGI1 was observed. These results raise the possibility of a novel role of Lgi1 within embryonic neurons through nuclear translocation and may provide insight into its potential effects on the development of the central nervous system and ADLTE pathogenesis.
Asunto(s)
Núcleo Celular/química , Citosol/química , Neuronas/química , Señales de Localización Nuclear , Proteínas/análisis , Proteínas/química , Telencéfalo/química , Transporte Activo de Núcleo Celular , Animales , Núcleo Celular/metabolismo , Células Cultivadas , Péptidos y Proteínas de Señalización Intracelular , Ratones , Ratones Endogámicos ICR , Ratones Noqueados , Mutación , Neuronas/metabolismo , Señales de Localización Nuclear/genética , Proteínas/genética , ARN Mensajero/biosíntesis , Telencéfalo/embriología , Telencéfalo/metabolismoRESUMEN
Here we use a comparative model to investigate how behavioral and physiological traits correlate with neural plasticity. Selection for divergent post-stress cortisol levels in rainbow trout (Oncorhynchus mykiss) has yielded low- (LR) and high responsive (HR) lines. Recent reports show low behavioral flexibility in LR compared to HR fish and we hypothesize that this divergence is caused by differences in neural plasticity. Genes involved in neural plasticity and neurogenesis were investigated by quantitative PCR in brains of LR and HR fish at baseline conditions and in response to two different stress paradigms: short-term confinement (STC) and long-term social (LTS) stress. Expression of proliferating cell nuclear antigen (PCNA), neurogenic differentiation factor (NeuroD) and doublecortin (DCX) was generally higher in HR compared to LR fish. STC stress led to increased expression of PCNA and brain-derived neurotrophic factor (BDNF) in both lines, whereas LTS stress generally suppressed PCNA and NeuroD expression while leaving BDNF expression unaltered. These results indicate that the transcription of neuroplasticity-related genes is associated with variation in coping style, while also being affected by STC - and LTS stress in a biphasic manner. A higher degree of neural plasticity in HR fish may provide the substrate for enhanced behavioral flexibility.
Asunto(s)
Adaptación Psicológica/fisiología , Plasticidad Neuronal/fisiología , Estrés Fisiológico/fisiología , Estrés Psicológico/fisiopatología , Análisis de Varianza , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Conducta Animal/fisiología , Peso Corporal/fisiología , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Cerebelo/química , Cerebelo/metabolismo , Proteínas de Dominio Doblecortina , Expresión Génica/genética , Expresión Génica/fisiología , Hidrocortisona/metabolismo , Hipotálamo/química , Hipotálamo/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Plasticidad Neuronal/genética , Neuropéptidos/metabolismo , Oncorhynchus mykiss , Antígeno Nuclear de Célula en Proliferación/metabolismo , Aislamiento Social , Estrés Fisiológico/genética , Estrés Psicológico/genética , Colículos Superiores/química , Colículos Superiores/metabolismo , Telencéfalo/química , Telencéfalo/metabolismoRESUMEN
The morphology of the telencephalon displays great diversity among different vertebrate lineages. Particularly the everted telencephalon of ray-finned fishes shows a noticeably different morphology from the evaginated telencephalon of nonray-finned fishes and other vertebrates. This makes the comparison between the different parts of the telencephalon of ray-finned fishes and other vertebrates difficult. Based on neuroanatomical, neurochemical, and connectional data no consensus on the subdivisions of the adult telencephalon of ray-finned fishes and their relation to nuclei in the telencephalon of other vertebrates has been reached yet. For tetrapods, comparative expression pattern analysis of homologous developmental genes has been a successful approach to clarify homologies between different parts of the telencephalon. In the larval zebrafish, subdivisions of the subpallium have been proposed using conserved developmental gene expression. In this study, we investigate the subdivisions of the adult zebrafish telencephalon by analyzing the expression pattern of conserved molecular marker genes. We identify the boundary between the pallium and subpallium based on the complementary expression of dlx2a, dlx5a in the subpallium and tbr1, neurod in the pallium. Furthermore, combinatorial expression of Isl, nkx2.1b, lhx1b, tbr1, eomesa, emx1, emx2, and emx3 identifies striatal-like, pallidal-like, and septal-like subdivisions within the subpallium. In contrast to previous models, we propose that the striatum and pallidum are stretched along the rostrocaudal axis of the telencephalon. Further, the septal nuclei derive from both the pallium and subpallium. On this basis, we present a new model for the subdivisions of the subpallium in teleost fish.
Asunto(s)
Regulación del Desarrollo de la Expresión Génica , Globo Pálido/anatomía & histología , Globo Pálido/química , Telencéfalo/anatomía & histología , Telencéfalo/química , Proteínas de Pez Cebra/biosíntesis , Proteínas de Pez Cebra/genética , Envejecimiento/genética , Envejecimiento/metabolismo , Envejecimiento/fisiología , Animales , Marcadores Genéticos/genética , Globo Pálido/metabolismo , Telencéfalo/metabolismo , Pez Cebra , Proteínas de Pez Cebra/químicaRESUMEN
The distribution of three types of arginine vasotocin (AVT) receptors in the brain and pituitary of the newt Cynops pyrrhogaster, namely, the V1a-, V2-, and V3/V1b-type receptors, was studied by means of in situ hybridization and immunohistochemistry. mRNA signals and immunoreactive cells for the V1a-type receptor were observed in the telencephalon (mitral layer of the olfactory bulb, dorsal and medial pallium, lateral and medial amygdala, bed nucleus of the decussation of the fasciculus telencephali, bed nucleus of the stria terminalis), diencephalon (anterior preoptic area, magnocellular preoptic nucleus, suprachiasmatic nucleus, ventral thalamus, dorsal and ventral hypothalamic nucleus), mesencephalon (tegmentum, interpeduncular nucleus), and medulla oblongata (median reticular formation, nucleus motorius tegmenti). Cells expressing the V2-type receptor were found in the telencephalon (medial pallium, lateral and medial amygdala, bed nucleus of the decussation of the fasciculus telencephali), and mesencephalon (tegmentum trigemini and facialis). In the paraphysis (possibly the main site of cerebrospinal fluid production), only V2-type receptor mRNA signal and immunoreactivity were detected. V3/V1b-type receptor mRNA was expressed in the diencephalon (dorsal hypothalamic nucleus, nucleus tuberculi posterioris), mesencephalon (tegmentum, interpeduncular nucleus), and medulla oblongata (raphe nucleus), whereas V3/V1b-type-receptor-like immunoreactivity was scarcely detectable in the entire brain. The V3/V1b-type receptor was predominantly expressed in the anterior pituitary. V3/V1b-type receptor and proopiomelanocortin mRNAs were co-localized in the distal lobe of the pituitary. This is the first report of the distribution of three types of AVT receptor in the brain and pituitary of non-mammalian vertebrates.
Asunto(s)
Química Encefálica , Adenohipófisis/química , Adenohipófisis/citología , Receptores de Vasopresinas/análisis , Salamandridae/metabolismo , Animales , Diencéfalo/química , Diencéfalo/citología , Técnica del Anticuerpo Fluorescente , Hibridación in Situ , Bulbo Raquídeo/química , Bulbo Raquídeo/citología , Mesencéfalo/química , Mesencéfalo/citología , Reacción en Cadena de la Polimerasa , ARN Mensajero , Receptores de Vasopresinas/aislamiento & purificación , Transducción de Señal , Telencéfalo/química , Telencéfalo/citologíaRESUMEN
The Dlx genes encode a family of transcription factors important for the development of the vertebrate forebrain. These genes have very similar expression domains during the development of the telencephalon in mice and play a role in gamma-aminobutyric acid (GABAergic) interneuron differentiation. We have used triple fluorescent in situ hybridization to study the relative expression domains of the dlx and gad1 genes in the zebrafish telencephalon and diencephalon. We also generated transgenic zebrafish with regulatory elements from the zebrafish dlx1a/2a locus. The zebrafish dlx regulatory elements recapitulated dlx expression in the forebrain and mimicked the relationship between the expression of the dlx genes and gad1. Finally, we show that a putative enhancer located downstream of dlx2b can also activate reporter gene expression in a tissue-specific manner similar to endogenous dlx2b expression. Our results indicate the dlx genes are regulated by an evolutionarily conserved genetic pathway and may play a role in GABAergic interneuron differentiation in the zebrafish forebrain.
Asunto(s)
Glutamato Descarboxilasa/análisis , Proteínas de Homeodominio/análisis , Prosencéfalo/metabolismo , Factores de Transcripción/análisis , Animales , Diencéfalo/química , Hibridación Fluorescente in Situ , Interneuronas/citología , Organismos Modificados Genéticamente , Prosencéfalo/crecimiento & desarrollo , Telencéfalo/química , Pez Cebra , Ácido gamma-AminobutíricoRESUMEN
The present study was focused on the morphology of the diencephalic nuclei (likely involved in reproductive functions) as well as on the distribution of GnRH (gonadotropin-releasing hormone) in the rhinencephalon, telencephalon and the diencephalon of the brain of bluefin tuna (Thunnus thynnus) by means of immunohistochemistry. Bluefin tuna has an encephalization quotient (QE) similar to that of other large pelagic fish. Its brain exhibits well-developed optic tecta and corpus cerebelli. The diencephalic neuron cell bodies involved in reproductive functions are grouped in two main nuclei: the nucleus preopticus-periventricularis and the nucleus lateralis tuberis. The nucleus preopticus-periventricularis consists of the nucleus periventricularis and the nucleus preopticus consisting of a few sparse multipolar neurons in the rostral part and numerous cells closely packed and arranged in several layers in its aboral part. The nucleus lateralis tuberis is located in the ventral-lateral area of the diencephalon and is made up of a number of large multipolar neurones. Four different polyclonal primary antibodies against salmon (s)GnRH, chicken (c)GnRH-II (cGnRH-II 675, cGnRH-II 6) and sea bream (sb)GnRH were employed in the immunohistochemical experiments. No immunoreactive structures were found with anti sbGnRH serum. sGnRH and cGnRH-II antisera revealed immunoreactivity in the perikarya of the olfactory bulbs, preopticus-periventricular nucleus, oculomotor nucleus and midbrain tegmentum. The nucleus lateralis tuberis showed immunostaining only with anti-sGnRH serum. Nerve fibres immunoreactive to cGnRH and sGnRH sera were found in the olfactory bulbs, olfactory nerve and neurohypophysis. The significance of the distribution of the GnRH-immunoreactive neuronal structures is discussed.
Asunto(s)
Química Encefálica , Encéfalo/anatomía & histología , Hormona Liberadora de Gonadotropina/análisis , Atún/anatomía & histología , Atún/metabolismo , Animales , Diencéfalo/química , Inmunohistoquímica , Neuronas/química , Vías Olfatorias/química , Telencéfalo/químicaRESUMEN
We examined the expression of mGlu2/3 metabotropic glutamate receptors in the retina of the goldfish Carassius auratus. mGlu2/3 receptors were expressed in all retinal layers internal to the photoreceptor layer, particularly in the outer and inner nuclear layers. Although the goldfish brain is able to tolerate prolonged periods of anoxia, we examined whether anoxia could induce retinal damage. Three hours of anoxia induced in the retina the development of apoptotic cell death, as assessed 48 h later by TUNEL staining. TUNEL-positive cells were particularly found in the inner and outer nuclear layers, and were also present in the ganglion cell layer. Pharmacological activation of mGlu2/3 receptors by systemic injection of LY379268 (0.5 mg/kg, i.p., 15 min before the onset of anoxia) substantially protected retinas against anoxia-induced cell death. In contrast, systemic injection of the mGlu2/3 receptor antagonist, LY341495 (1 mg/kg, i.p., 15 min before the onset of anoxia), significantly amplified cell death. Finally, as mGlu2/3 receptors are implicated in the control of extracellular glutamate concentrations, we examined the stimulation of glutamate release in isolated goldfish retinas. Depolarizing medium containing 30 mM KCl led to a significant increase in glutamate release, which was substantially reduced by LY379268. We conclude that activation of mGlu2/3 receptors may provide a major defensive mechanism against ischemic/anoxic retinal damage.
Asunto(s)
Aminoácidos/uso terapéutico , Compuestos Bicíclicos Heterocíclicos con Puentes/uso terapéutico , Hipoxia/prevención & control , Receptores de Glutamato Metabotrópico/metabolismo , Retina/metabolismo , Enfermedades de la Retina/prevención & control , Aminoácidos/farmacología , Animales , Apoptosis , Western Blotting/métodos , Antagonistas de Aminoácidos Excitadores/farmacología , Ácido Glutámico/metabolismo , Carpa Dorada , Hipoxia/metabolismo , Hipoxia/patología , Hipoxia Encefálica/metabolismo , Hipoxia Encefálica/patología , Inmunohistoquímica/métodos , Etiquetado Corte-Fin in Situ , Modelos Animales , Receptores de Glutamato Metabotrópico/análisis , Receptores de Glutamato Metabotrópico/antagonistas & inhibidores , Retina/efectos de los fármacos , Retina/patología , Enfermedades de la Retina/metabolismo , Enfermedades de la Retina/patología , Telencéfalo/química , Xantenos/farmacologíaRESUMEN
1. Nucleosides potentially participate in the neuronal functions of the brain. However, their distribution and changes in their concentrations in the human brain is not known. For better understanding of nucleoside functions, changes of nucleoside concentrations by age and a complete map of nucleoside levels in the human brain are actual requirements. 2. We used post mortem human brain samples in the experiments and applied a recently modified HPLC method for the measurement of nucleosides. To estimate concentrations and patterns of nucleosides in alive human brain we used a recently developed reverse extrapolation method and multivariate statistical analyses. 3. We analyzed four nucleosides and three nucleobases in human cerebellar, cerebral cortices and in white matter in young and old adults. Average concentrations of the 308 samples investigated (mean+/-SEM) were the following (pmol/mg wet tissue weight): adenosine 10.3+/-0.6, inosine 69.5+/-1.7, guanosine 13.5+/-0.4, uridine 52.4+/-1.2, uracil 8.4+/-0.3, hypoxanthine 108.6+/-2.0 and xanthine 54.8+/-1.3. We also demonstrated that concentrations of inosine and adenosine in the cerebral cortex and guanosine in the cerebral white matter are age-dependent. 4. Using multivariate statistical analyses and degradation coefficients, we present an uneven regional distribution of nucleosides in the human brain. The methods presented here allow to creation of a nucleoside map of the human brain by measuring the concentration of nucleosides in microdissected tissue samples. Our data support a functional role for nucleosides in the brain.
Asunto(s)
Corteza Cerebral/química , Nucleósidos/análisis , Purinas/análisis , Pirimidinas/análisis , Telencéfalo/química , Adulto , Factores de Edad , Anciano de 80 o más Años , Química Encefálica , Cromatografía Líquida de Alta Presión , Análisis por Conglomerados , Humanos , Cambios Post MortemRESUMEN
Effects of aging and oxidative stress were studied in cerebral microvessels and microvessel-depleted brain from 6-, 18-, and 24-month-old C57Bl/6J mice exposed to normoxia, 24 or 48 h hyperoxia, or 24 h hyperoxia followed by 24 h normoxia. Microvessels lacked smooth muscle and consisted predominantly of endothelium. Following exposure and isolation of microvessel and parenchymal proteins, Western blot analysis was performed for detection of cytosolic thioredoxin 1 (TRx 1) and mitochondrial thioredoxin 2 (TRx 2), protein carbonyl, and mitochondrial superoxide dismutase (MnSOD). Both microvessel and parenchymal TRx 1 levels were increased by hyperoxia; however, the microvascular response was limited and delayed in comparison to that of the parenchymal fraction. Whereas TRx 2 levels in microvessels were increased in older mice, irrespective of exposure condition, hyperoxia per se had little or no apparent effect. Parenchymal cells showed no age-related increase in TRx 2 level under normoxic conditions, but showed increased levels following hyperoxia. Microvessel MnSOD was lower than that in parenchymal cells, but increased with age under normoxia, and also was correlated with the duration of hyperoxia. Although hyperoxia augmented MnSOD levels in young (6 months) and middle-aged (18 months) animals, the response was less pronounced in microvessels from senescent, 24-month-old mice. Unlike microvessels, which showed a sustained age-related increase in MnSOD level under each exposure condition, parenchymal cells from normoxic mice showed no increase, and hyperoxia-induced elevations declined with prolonged 48 h exposure. These results indicate that the microvessel endothelium is (1) subjected to a more intense oxidative environment than neurons and glia and (2) is limited by aging in its ability to respond to oxidative insult.
Asunto(s)
Envejecimiento , Hiperoxia/metabolismo , Microcirculación/metabolismo , Estrés Oxidativo , Telencéfalo/irrigación sanguínea , Animales , Análisis de los Gases de la Sangre , Western Blotting , Química Encefálica , Separación Celular , Citosol/metabolismo , Electroforesis en Gel de Poliacrilamida , Endotelio Vascular/química , Endotelio Vascular/citología , Endotelio Vascular/metabolismo , Proteínas de la Membrana/análisis , Proteínas de la Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Microcirculación/química , Microcirculación/citología , Mitocondrias/enzimología , Músculo Liso Vascular/citología , Músculo Liso Vascular/metabolismo , Superóxido Dismutasa/metabolismo , Telencéfalo/química , Telencéfalo/citología , Tiorredoxinas/análisis , Tiorredoxinas/metabolismo , Factores de TiempoRESUMEN
The distribution of galanin-like immunoreactive perikarya and nerve fibers in the brain of the snake Bothrops jararaca was studied by means of immunohistochemistry using an antiserum against porcine galanin. Immunoreactive neurons were only detected in the infundibular recess nucleus. Immunoreactive fibers were found in the telencephalic, diencephalic and mesencephalic areas such as the dorsal cortex, nucleus accumbens, lamina terminalis, preoptic area, mediodorsal region of the supraoptic nucleus, subfornical organ, nucleus of the paraventricular organ, subcommisural organ and periventricular grey region. The habenula, paraventricular nucleus, infundibular recess nucleus and hypothalamo-hypophyseal tract presented denser innervations. The outer layer of the median eminence displayed numerous fibers located close to the portal system, while scarce fibers were seen in the inner median eminence and neural lobe of the hypophysis. The distribution of labelled neurons in the brain of this snake was more restricted than that described in a turtle. The wide hypothalamic and extrahypothalamic distribution of labelled fibers suggests that galanin peptides may have hypophysiotropic, neuromodulator and neurotransmitter roles in the snake B. jararaca.
Asunto(s)
Bothrops/fisiología , Química Encefálica , Galanina/análisis , Animales , Tronco Encefálico/química , Diencéfalo/química , Femenino , Galanina/inmunología , Inmunohistoquímica , Masculino , Neuronas/química , Telencéfalo/químicaRESUMEN
A method of pinpoint-sampling followed by on-line pre-concentration of the sample, throughout in-capillary derivatization and capillary electrophoretic separation was evaluated by demonstrating the detection of taurine, 2-aminoethanesulfonic acid at a specific location of a rat brain. The direct sampling of taurine from the rat brain was accomplished by using voltage injection associated with two kinds of driving forces, electrophoretic flow and electroosmotic flow (EOF). The capillary tube (75 microm of inner diameter x 375 microm of outer diameter) of the capillary electrophoresis (CE) apparatus was already filled with a CE run buffer, viz., 40 mM phosphate-borate buffer (pH 10) containing 2mM o-phthalaldehyde (OPA)/N-acetylcysteine (NAC) as the derivatization reagent. One end of a platinum wire (0.5mm o.d.), used as the anode, and the inlet end of capillary tube (from which a 1.0 cm long polyimide coating was removed), were pricked down onto the surface of either the cerebrum or cerebellum of a rat brain at a location of very small dimension. When a low voltage (5 kV, 30s) was applied, taurine began to move from the rat brain into the capillary tube, and, simultaneously, electric focusing of taurine occurred by the action of "the pH-junction effect" at the inlet end of the capillary tube. After completing the injection, both the platinum wire and capillary tube were detached from the brain and dipped into the run buffer in an anode reservoir filed with the same solution as that in the capillary tube for the CE apparatus. Then, by applying a high voltage (20 kV) between the ends of the capillary tube, taurine was automatically derivatized to yield the fluorescent derivative, separated and detected with fluorescence (E(x)=340 nm, E(m)=455 nm) during migration throughout the capillary tube. The migration profiles obtained from cerebrum and cerebellum appeared to be different, but the peak corresponding to taurine was identified on both electropherograms. The efficacy of the present method including sample on-line pre-concentration prior to throughout in-capillary derivatization CE was first verified with several preliminary experiments by using samples of taurine in water, saline and a piece of 1.5% agar-gel block, as an alternate standard for the rat brain used in this study.