960 resultados para Projection Neurons


Relevância:

20.00% 20.00%

Publicador:

Resumo:

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

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The NADPH-diaphorase (NADPH-d) positive myoenteric neurons from the body of the stomach of rats with streptozotocin-induced diabetes with or without supplementation with acetyl-L-carnitine (ALC) were evaluated. At the age of 105 days the animals were divided into four groups: normoglycaemic (C), normoglycaemic supplemented with ALC (CC), diabetic (D) and diabetic supplemented with ALC (DC). The supplementation with ALC (200 mg/kg body weight/day) to groups CC and DC was made during 105 days. After this period the animals were killed and the stomach removed and subjected to the histochemical technique of NADPH-d for the staining of the neurons of the myoenteric plexus. The area of 500 neurons of each group was investigated, as well as the neuronal density in an area of 23.84 mm(2) in each stomach. ALC promoted reduction (P < 0.05) of fasting glycaemia, water ingestion and areas of the profiles of the cell bodies of the NADPH-d neurons in the diabetic animals. The density of these neurons was not statistically different in the groups studied. It is suggested, therefore, a moderate neuroprotective effect of ALC, because the diminishment of the areas of the neuronal profiles in the supplemented diabetic animals, although being statistically significant relative to the non-supplemented diabetics, was not sufficient to equal the values from the non-diabetic controls.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this work, we investigated the effect of the acetyl-L-carnitine (ALC) supplementation (200 mg/kg/day) on the myenteric neurons of the ileum of rats made diabetic by streptozotocin (35 mg/kg, i.v.). Four groups were used: diabetic (D), diabetic supplemented with ALC (DC), control (C) and control supplemented with ALC (CC). After 15 weeks of diabetes induction the animals were killed and the ileum was collected and subjected to whole-mount preparation to evidence the myenteric neurons through the histochemical technique of the NADH-diaphorase. The density of neurons seen in 12.72 min(2) of ileum showed no difference among the groups, although in group D it was 22% smaller than in group C, while group DC was 9% smaller to group CC. The profiles of the cell bodies (PC) of 1000 neurons per group were analysed. The neurons PC in group D decreased (P < 0.0001) when compared with other groups and increased (P < 0.0001) when compared with group DC. The incidence of neurons with a PC inferior to 200 mu m(2) was larger in group D. The frequency of neurons with a PC higher than 200 mu m(2) in group DC was close to those seen in groups C and CC. We concluded that ALC eases the loss of neurons and makes the incidence of myenteric neurons with a PC higher than 200 mu m(2) similar to the control rats.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

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

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this study, two circadian related centres, the suprachiasmatic nucleus (SCN) and the intergeniculate leaflet (IGL) were evaluated in respect to their cytoarchitecture, retinal afferents and chemical content of major cells and axon terminals with a tract tracer and immunohistochemical techniques in the rock cavy (Kerodon rupestris), a Brazilian caviidae rodent species. The rock cavy SCN is innervated in its ventral portion by terminals from the predominantly contralateral retina. It also contains neurophisin and vasoactive intestinal polypeptide immunoreactive cell bodies and neuropeptide Y and enkephalin immunopositive fibres and terminals and is marked by intense GFAP immunoreactivity. The IGL receives a predominantly contralateral retinal projection, contains neuropeptide Y and nitric oxide synthase producing neurons and enkephalin immunopositive terminals and is characterized by dense GFAP immunoreactivity. This is the first report examining the neural circadian system in a crepuscular rodent species for which circadian properties have been described. The results are discussed comparing with what has been described for other species and in the context of the functional significance of these centres

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The circadian timing system (CTS) is responsible for the generation and synchronization and the suprachiasmatic nucleus (SCN) of the hypothalamus has been described as the major circadian pacemaker in many mammalian species. The internal temporal organization managed by SCN is disturbed with aging bringing many pathological disorders that range from loss of complex cognitive performance to simple physiological functions. Therefore, our aim was perform a comparative study of the morphological aspects and neurochemical composition in the SCN of marmosets (Callithrix jacchus) adults and older using immunohistochemical techniques. We found morphometric and neurochemical changes in th SCN o folder animals in comparison to adults, among these a possible decreased in retinal projection to the SCN of older animals, found through a decline in CTB immunostaining, which can occur due atrophy and/or decreasing of fibers from the retinohypothalamic tract (RHT). The Klüver-Barrera histological technique strongly suggests a decrease in those fibers from RHT. Also, by means of a morphometric study, it is found a atrophy and numerical decline of neurons in SCN of aged animals, investigated by Nissl technique, and immunostaining with NeuN and calbindin. Relative optical density (ROD) analysis were used to evaluate the expression of some neurochemical components in SCN, such as GFAP expression, which was increased in older, result that indirectly reinforces that morphological changes occurs due the aging; the vasoactive intestinal polipeptide (VIP) showed no expression alteration in SCN of older animals; the serotonin (5-HT) was descreased in the dorsomedial portion of the SCN, and neurpeptide Y (NPY) apparently also decrease due to the increase of age. Many of these modifications were seen in other animals, such as rodents, human primates and non-human primates. These data about marmoset comes to add new information of the effect of aging on structures responsibles for the circadian rhytmicity, and that some behavioral changes controlled by th SCN, and founded in aged animals, may be caused by these morphological and neurochemical changes. Although some results have been quantitatively negative, qualitatively all analysis show significant change comparing adult and older animals, perhaps due to a low sampling number. In conclusion, the marmoset presents several morphological and neurochemical changes in the SCN of aged animals compared to adults, which may result in behavioral changes that favor pathology aging related

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The retinal projections in mammals usually reach, classically, three major functional systems: the primary visual system, the accessory optic system, and the circadian timing system. But the retinal projections also reach areas classically considered non-visual, one of which groups the neurons of the zona incerta (ZI), target this study. The primary visual system includes thalamic lateral geniculate complex is formed by the dorsal lateral geniculate nucleus, intergeniculate leaflet and the ventral lateral geniculate nucleus and other Components. The accessory optic system is composed of the small nuclei: nuclei terminal dorsal, lateral, medial and the interstitial nucleus of the superior posterior fasciculus. These nuclei are involved in visuo-motor activities. The circadian timing system is comprised of the suprachiasmatic nucleus of the hypothalamus, that act as master circadian pacemaker, entraining pathways and efferents pathways to the efectors, and the intergeniculate leaflet, that seems to act as a modulator of the pacemaker. The retinal projections too reach classically considered non-visual areas, including the zona incerta. This region is localized in the ventral thalamus and has been implicated in various functional properties including nociceptive and somatosensory processing, motor response, sociosexual behaviour, feeding and drinking, in symptoms of neurodegenerative diseases, arousal and attention. It also displays connection with several areas of central nervous system. The aim of this study was characterize the retinal projection in the zona incerta of Callithrix jacchus (sagüi), a primate of the New World through the anterograde axonal transport of the cholera toxin subunit b and analyze the citoarchicteture using Nissl and NeuN, and neurochemical substances such as serotonin, GABA, VIP, VP, GFAP and binding-calcium proteins. The zona incerta showed a different division of the literature in citoarquitetura, both by means of Nissl as neurochemical by NeuN, with a subdivision ventrolateral and dorsomedial. The neurochemical to the other substances corroborate with this subdivision. The GFAP was almost completely negative for the zona incerta, result non evidenced in previous studies yet. The 16 retinal projection in sagüi, unlike other primates and rodents, reached the caudal portion only. This work helps to make further studies are conducted based on this subdivision and the localization of the neurochemical substances associated with possible behaviors that the zona incerta is involved

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The parabrachial complex (PB) is an area of the brainstem responsible for the processing and transmission of essential physiologic information for the survival of the organisms. This region is subdivided in approximately nine subregions, considering morphology, cytoarchitectural and functional characteristic. Its neurons have an extensive network of connections with other regions of the nervous system. The objective in this work was to map the retinal projection to the PB and make a citoarchitectonic and neurochemical characterization of this region in the common marmoset (Callithrix jacchus), a primate of the New World. The retinal projections were mapped by anterograde transport of the choleric toxin subunit b (CTb). The citoarchitecture was described through the Nissl method, and the neurochemical characterization was made through immunohistochemical technique to the some neurotransmitters and neuroactives substances present in this neural center. In marmoset PB, in the coronal sections labeled by Nissl method, we found a similar pattern to that evidenced in other animal species. The immunoreactivity against CTb was verified in the PBMv in fibers/terminal, characterizing such as retinal innervations in this area. The immunohistochemical technique reveled that the PB contain cells, fibers and/or terminals immunoreactives to the neuronal nuclear protein, Choline acetyl transferase, nitric oxide synthase, serotonin, enkephalin, substance P, Calcium-binding proteins (calbindin, calretinin e parvalbumin), and glial fibrillary acidic protein. The histochemical technique reveled cells and fibers NADPH-diaphorase reactive. Each one of those substances presented a characteristic pattern of demarcation in PB, and some serve as specific markers of subregions

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We studied the distribution of NADPH-diaphorase (NADPH-d) activity in the prefrontal cortex of normal adult Cebus apella monkeys using NADPH-d histochemical protocols. The following regions were studied: granular areas 46 and 12, dysgranular areas 9 and 13, and agranular areas 32 and Oap. NADPH-d-positive neurons were divided into two distinct types, both non-pyramidal. Type I neurons had a large soma diameter (17.24 +/- 1.73 pm) and were densely stained. More than 90% of these neurons were located in the subcortical white matter and infragranular layers. The remaining type I neurons were distributed in the supragranular layers. Type II neurons had a small, round or oval soma (9.83 +/- 1.03 mu m), and their staining pattern varied markedly. Type II neurons were distributed throughout the cortex, with their greatest numerical density being observed in layers II and III. In granular areas, the number of type II neurons was up to 20 times that of type I neurons, but this proportion was smaller in agranular areas. Areal density of type II neurons was maximum in the supragranular layers of granular areas and minimum in agranular areas. Statistical analysis revealed that these areal differences were significant when comparing some specific areas. In conclusion, our results indicate a predominance of NADPH-d-positive cells in supragranular layers of granular areas in the Cebus prefrontal cortex. These findings support previous observations on the role of type II neurons as a new cortical nitric oxide source in supragranular cortical layers in primates, and their potential contribution to cortical neuronal activation in advanced mammals. (c) 2006 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The nucleus of the solitary tract (NTS) receives primary afferents involved in cardiovascular regulation. We investigated the role of NK1-receptor bearing neurons in the NTS on cardiovascular reflexes in awake rats fitted with chronic venous and arterial cannulae. These neurons were lesioned selectively with saporin conjugated with substance P (SP-SAP, 2 mu M, bilateral injections of 20 nL in the subpostremal NTS, or 200 nL in both the subpostremal and the commissural NTS). Before, and 7 and 14 days after injection of SP-SAP, we measured changes in blood pressure and heart rate induced by i.v. injection of phenylephrine and nitroprusside (baroreceptor reflex), cyanide (arterial chemoreceptor reflex), and phenylbiguanide (Bezold-Jarisch reflex). The smaller injections with SP-SAP completely abolished NK1 receptor staining in the subpostremal NTS. The larger injections abolished NK1 receptor immunoreactivity in an area that extended from the commissural NTS to the rostral end of the subpostremal NTS. The lesions seemed to affect only a limited number of neurons, since neutral red stained sections did not show any obvious reduction in cell number. The smaller lesions reduced the gain of baroreflex bradycardia and the hypotension induced by phenylbiguanide. The larger lesions completely abolished the response to phenylbiguanide, blocked the baroreflex bradycardia induced by phenylephrine, severely blunted the baroreflex tachycardia, and blocked the bradycardia and reduced the hypertension induced by cyanide. Thus, these responses depend critically on NK1-receptor bearing neurons in the NTS. (c) 2006 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The ultrastructural characteristics and the morphometric evaluation of the different types of neurons present in the dorsal root ganglia (DRG) of the South American opossum (Didelphis albiventris) were studied. Four adult male animals were used and the neurons from cervical and lumbar DRG were removed and processed for histological and transmission electron microscopy observations. The morphometric data were obtained from serial sections stained by H/E and Masson's trichrome. The number of neurons in cervical and lumbar DRG was 22 300 and 31 000, respectively. About 68% of the cervical neurons and 62.5% of the lumbar neurons presented areas up to 1300 mu m(2) and were considered as the small neurons of the DRG. The ultrastructural observations revealed two morphological types of neurons: clear large neurons and dark small neurons. The nuclei of both cell types are spherical and the chromatin is disperse and rarefected. The cytoplasm of the dark small neuron is more electron dense and shows a regular distribution of small mitochondria and many rough reticulum cisterns in the periphery. A small Golgi apparatus was close to the nucleus and many disperse neurofilaments occupy most parts of the cytoplasm. Smooth reticulum cisterns are rare and lipofucsin-like inclusions are present at some points. In the clear large neurons, the organelles are homogenously scattered through the cytoplasm. The neurofilaments are close packed forming bundles and small mitochondria and rough reticulum cisterns are disperse. Lipofucsin-like inclusions are more frequent in these cells.