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Mechanisms involved in the pressor response to noradrenaline microinjection into the supraoptic nucleus of unanesthetized rats

BUSNARDO, Cristiane; TAVARES, Rodrigo Fiacadori; CORREA, Fernando Morgan Aguiar
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
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We report on the cardiovascular effects of noradrenaline (NA) microinjection into the hypothalamic supraoptic nucleus (SON) as well as the central and peripheral mechanisms involved in their mediation. Microinjections of NA 1, 3, 10, 30 or 45 nmol/100 nL into the SON caused dose-related pressor and bradycardiac response in unanesthetized rats. The response to NA 10 nmol was blocked by SON pretreatment with 15 nmol of the alpha(2)-adrenoceptor antagonist RX821002 and not affected by pretreatment with equimolar dose of the selective alpha(1)-adrenoceptor antagonist WB4101, suggesting that local alpha(2)adrenoceptors mediate these responses. Pretreatment of the SON with the nonselective beta-adrenoceptor antagonist propranolol 15 nmol did not affect the pressor response to NA microinjection of into the SON. Moreover, the microinjection of the 100 nmol of the selective alpha(1)-adrenoceptor agonist methoxamine (MET) into the SON did not cause cardiovascular response while the microinjection of the selective alpha(2)adrenoceptor agonists BHT920 (BHT, 100 nmol) or clonidine (CLO, 5 nmol) caused pressor and bradycardiac responses, similar to that observed after the microinjection of NA. The pressor response to NA was potentiated by intravenous pretreatment with the ganglion blocker pentolinium and was blocked by intravenous pretreatment with the V(1)-vasopressin receptor antagonist dTyr(CH2)5(Me)AVP...

Stimulation-Produced Analgesia From the Occipital or Retrosplenial Cortex of Rats Involves Serotonergic and Opioid Mechanisms in the Anterior Pretectal Nucleus

REIS, Glaucia Melo; ROSSANEIS, Ana Carolina; SILVEIRA, Joao Walter S.; DIAS, Quintino Moura; PRADO, Wiliam A.
Fonte: CHURCHILL LIVINGSTONE Publicador: CHURCHILL LIVINGSTONE
Tipo: Artigo de Revista Científica
ENG
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The electrical stimulation of the occipital (OC) or retrosplenial (RSC) cortex produces antinociception in the rat tail-flick test. These cortices send inputs to the anterior pretectal nucleus (APtN) which is implicated in antinociception and nociception. At least muscarinic cholinergic, opioid, and serotonergic mechanisms in the APtN are involved in stimulation-produced antinociception (SPA) from the nucleus. In this study, the injection of 2% lidocaine (.25 mu L) or methysergide (40 and 80 ng/.25 mu L) into the APtN reduced the duration but did not change the intensity of SPA from the OC, whereas both duration and intensity of SPA from the RSC were significantly reduced in rats treated with lidocaine or naloxone (10 and 50 ng/.25 mu L), injected into the ANN. Naloxone or methysegide injected into the APtN was ineffective against SPA from the OC or RSC, respectively. Atropine (100 ng/.25 mu L) injected into the ANN was ineffective against SPA from either the OC or RSC. We conclude that the APtN acts as an intermediary for separate descending pain inhibitory pathways activated from the OC and RSC, utilizing at least serotonin and endogenous opioid as mediators in the nucleus. Perspective: Stimulation-induced antinociception from the retrosplenial or occipital cortex in the rat tail-flick test depends on the activation of separate descending pain inhibitory pathways that utilize the APtN as a relay station. (C) 2011 by the American Pain Society; FAPESP; CAPES

Glomerular Nucleus of the Weakly Electric Fish, Gymnotus sp.: Cytoarchitecture, Histochemistry, and Fiber Connections-Insights from Neuroanatomy to Evolution and Behavior

GIASSI, Ana Catarina Casari; MALER, Leonard; MOREIRA, Jorge E.; HOFFMANN, Anette
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
ENG
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The present study provides a detailed description of morphological and hodological aspects of the glomerular nucleus in the weakly electric fish Gymnotus sp., and explores the evolutionary and functional implications flowing from this analysis. The glomerular nucleus of Gymnotus shows numerous morphological similarities with the glomerular nucleus of percomorph fish, although cytoarchitectonically simpler. In addition, congruence of the histochemical acetylcholinesterase (AChE) distribution with cytoarchitectonic data suggests that the glomerular nucleus, together with the ventromedial cell group of the medial subdivision of the preglomerular complex (PGm-vmc) rostrally, and the subglomerular nucleus (as identified by Maler et al. [1991] J Chem Neuroanat 4:1-38) caudally, may form a distinct longitudinally organized glomerular complex. Our results show that an important source of sensory afferents to the glomerular nucleus originates in the pretectal and electrosensorius nuclei. The glomerular nucleus in turn projects to the hypothalamus (inferior lobe and anterior hypothalamus), to the anterior tuberal nucleus, and to the medial region of the preglomerular nucleus (PGm). These data suggest that visual and electrosensory information reach the glomerular nucleus and are relayed to the hypothalamus and...

Immunocytochemical characterization of the pregeniculate nucleus and distribution of retinal and neuropeptide Y terminals in the suprachiasmatic nucleus of the Cebus monkey

PINATO, L.; FRAZAO, R.; CRUZ-RIZZOLO, R. J.; CAVALCANTE, J. S.; NOGUEIRA, M. I.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
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Circadian rhythms generated by the suprachiasmatic nucleus (SCN) are modulated by photic and non-photic stimuli. In rodents, direct photic stimuli reach the SCN mainly through the retinohypothalamic tract (RHT), whereas indirect photic stimuli are mainly conveyed by the geniculohypothalamic tract (GHT). In rodents, retinal cells form a pathway that reaches the intergeniculate leaflet (IGL) where they establish synapses with neurons that express neuropeptide Y (NPY), hence forming the GHT projecting to the SCN. In contrast to the RHT, which has been well described in primates, data regarding the presence or absence of the IGL and GHT in primates are contradictory. Some studies have suggested that an area of the pregeniculate nucleus (PGN) of primates might be homologous to the IGL of rodents, but additional anatomical and functional studies on primate species are necessary to confirm this hypothesis. Therefore, this study investigated the main histochemical characteristics of the PGN and the possible existence of the GHT in the SCN of the primate Cebus, comparing the distribution of NPY immunoreactivity, serotonin (5-HT) immunoreactivity and retinal terminal fibers in these two structures. The results show that a collection of cell bodies containing NPY and serotonergic immunoreactivity and retinal innervations are present within a zone that might be homologous to the IGL of rodents. The SCN also receives dense retinal innervations and we observed an atypical distribution of NPY- and 5-HT-immunoreactive fibers without regionalization in the ventral part of the nucleus as described for other species. These data may reflect morphological differences in the structures involved in the regulation of circadian rhythms among species and support the hypothesis that the GHT is present in some higher primates (diurnal animals). (C) 2009 Elsevier B.V. All rights reserved.; FAPESP (Funda Ao de Amparo A Pesquisa do Estado de Sao Paulo); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); CAPES (coordena Ao de aperfeicoamento de pessoal de nivel superior); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Department of Neurology and Anatomy...

PARAVENTRICULAR AND SUPRAOPTIC NUCLEI OF THE HYPOTHALAMUS MEDIATE CARDIOVASCULAR RESPONSES EVOKED BY THE MICROINJECTION OF NORADRENALINE INTO THE MEDIAL AMYGDALOID NUCLEUS OF THE RAT BRAIN

Fortaleza, E. A. T.; Scopinho, A. A.; Correa, F. M. A.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD Publicador: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD
Tipo: Artigo de Revista Científica
ENG
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The medial amygdaloid nucleus (MeA) is a part of the limbic system and is involved in cardiovascular modulation. We previously reported that microinjection of noradrenaline (NA) into the MeA of unanesthetized rats caused pressor and bradycardiac responses, which were mediated by acute vasopressin release into the systemic circulation. In the present study, we tested the possible involvement of magnocellular neurons of the paraventricular (PVN) and/or supraoptic (SON) of the hypothalamus that synthesize vasopressin in the cardiovascular pathway activated by the microinjection of NA into the MeA. Pressor and bradycardiac responses to the microinjection of NA (27 nmol/100 nL) into the MeA were blocked by pretreatment of either the PVN or the SON with cobalt chloride (CoCl2, 1 mM/100 nL), thus indicating that both hypothalamic nuclei mediate the cardiovascular responses evoked by microinjection of NA Into the MeA. Our results suggest that the pressor and bradycardiac response caused by the microinjection of NA into the MeA is mediated by magnocellular neurons in both the PVN and SON. (C) 2012 IBRO. Published by Elsevier Ltd. All rights reserved.; CNPq; CNPq [140118/2009-8, 501269/2005-3]; CAPES; CAPES [PNPD0176087]

Involvement of the basolateral complex and central nucleus of amygdala in the omission effects of different magnitudes of reinforcement

Judice-Daher, Danielle M.; Tavares, Tatiane Ferreira; Bueno, Jose Lino Oliveira
Fonte: ELSEVIER SCIENCE BV; AMSTERDAM Publicador: ELSEVIER SCIENCE BV; AMSTERDAM
Tipo: Artigo de Revista Científica
ENG
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Evidence from appetitive Pavlovian and instrumental conditioning studies suggest that the amygdala is involved in modulation of responses correlated with motivational states, and therefore, to the modulation of processes probably underlying reinforcement omission effects. The present study aimed to clarify whether or not the mechanisms related to reinforcement omission effects of different magnitudes depend on basolateral complex and central nucleus of amygdala. Rats were trained on a fixed-interval 12 s with limited hold 6 s signaled schedule in which correct responses were always followed by one of two reinforcement magnitudes. Bilateral lesions of the basolateral complex and central nucleus were made after acquisition of stable performance. After postoperative recovery, the training was changed from 100% to 50% reinforcement schedules. The results showed that lesions of the basolateral complex and central nucleus did not eliminate or reduce, but interfere with reinforcement omission effects. The response from rats of both the basolateral complex and central nucleus lesioned group was higher relative to that of the rats of their respective sham-lesioned groups after reinforcement omission. Thus, the lesioned rats were more sensitive to the omission effect. Moreover...

Retinal projections and neurochemical characterization of the pregeniculate nucleus of the common marmoset (Callithrix jacchus)

Lima, Ruthnaldo R. M.; Pinato, Luciana; Nascimento, Rayane B. S.; Engelberth, Rovena Clara G. J.; Nascimento Junior, Expedito S.; Cavalcante, Judney C.; Britto, Luiz R. G.; Costa, Miriam S. M. O.; Cavalcante, Jeferson S.
Fonte: Elsevier Science BV; Amsterdam Publicador: Elsevier Science BV; Amsterdam
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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In mammals, the suprachiasmatic nucleus (SCN) and the intergeniculate leaflet (IGL) are the main components of the circadian timing system. The SCN is the site of the endogenous biological clock that generates rhythms and synchronizes them to environmental cues. The IGL is a key structure that modulates SCN activity and is responsible for the transmission of non-photic information to the SCN, thus participating in the integration between photic and non-photic stimuli. Both the SCN and IGL receive projections of retinal ganglion cells and the IGL is connected to the SCN through the geniculohypothalamic tract. Little is known about these structures in the primate brain and the pregeniculate nucleus (PGN) has been suggested to be the primate equivalent of the rodent IGL. The aim of this study was to characterize the PGN of a primate, the common marmoset (Callithrix jacchus), and to analyze its retinal afferents. Here, the marmoset PGN was found to be organized into three subsectors based on neuronal size, pattern of retinal projections, and the distribution of neuropeptide Y-, GAD-, serotonin-, enkephalin- and substance P-labeled terminals. This pattern indicates that the marmoset PGN is equivalent to the IGL. This detailed description contributes to the understanding of the circadian timing system in this primate species considering the importance of the IGL within the context of circadian regulation. (C) 2012 Elsevier B.V. All rights reserved.; CNPq; CNPq; CAPES; CAPES; PROPESQ-UFRN; PROPESQUFRN; FAPESP; FAPESP

Origem da inervação dopaminérgica da divisão central da amígdala expandida e da concha do núcleo Acumbens no rato.; Origin of dopaminergic fibers to the central extended amygdala and nucleus accumbens shell in the rat.

Hasue, Renata Hydee
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 23/01/2001 PT
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A amígdala expandida central (EAc) inclui os núcleos central da amígdala (CeA), intersticial lateral da estria terminal (BSTl), intersticial do ramo posterior da comissura anterior (IPAC) e amígdala expandida sublenticular (SLEA). A EAc e a concha do acumbens possuem densa inervação dopaminérgica, implicada em processos motivacionais, e cuja origem foi estudada com a técnica de dupla marcação celular, combinando-se imunofluorescência para o traçador retrógrado Fluoro-Gold e para a tirosina hidroxilase. Nossos resultados indicam que a inervação dopaminérgica do CeA e BSTl é semelhante, se originando em igual proporção da área tegmental ventral (A10) e do núcleo dorsal da rafe/substância cinzenta periaquedutal (A10dc). A inervação dopaminérgica da SLEA, IPAC e concha do acumbens se origina principalmente do grupo A10. Com um anticorpo específico para dopamina vimos que parte da projeção do A10dc para o CeA é de fato dopaminérgica. Os grupos dopaminérgicos diencefálicos não inervam a EAc e a concha do acumbens.; The central extended amygdala (EAc) includes the central amygdaloid nucleus (CeA), lateral bed nucleus of the stria terminalis (BSTl), interstitial nucleus of the posterior limb of the anterior commissure (IPAC) and sublenticular extended amygdala (SLEA). The dopaminergic innervation of the EAc and nucleus accumbens shell is functionally related to motivational processes. Its origin was studied by combining immunofluorescence to tyrosine hydroxylase and Fluoro-Gold...

Eferências do núcleo lateral superior da oliva no rato (rattus norvegicus).; Efferences of lateral superior olive nucleus in the rat ( rattus norvegicus)

Souto, Suzana Souza
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 22/10/2007 PT
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Após a descrição da Urocortina 1, um neuropeptídeo encontrado principalmente no núcleo de Edinger-Westphal e no núcleo lateral superior da oliva (LSO), atentou-se para a ausência do conhecimento das projeções de ambos os núcleos. Nós pretendemos contribuir para o conhecimento das projeções ascendentes e descendentes do LSO, usando um traçador neuronal anterógrado. Nós utilizamos o Biotin-Dextran-Amine (BDA) injetado no LSO de ratos, 15 a 20 dias depois os ratos eram perfundidos, os encéfalos e medulas foram seccionados e tratados histoquimicamente. Nós encontramos que existem 4 vias eferentes do LSO, tanto ascendentes como descendentes no sistema nervoso central, como segue: duas vias ascendentes, uma ipsilateral à injeção, a mais proeminente e a via contralateral que é menos densa; duas vias descendentes, uma ipsilateral muito menos evidente, e a contralateral que é moderada. Seguindo a via ascendente ipsilateral, nós encontramos as seguintes estruturas bem marcadas com BDA: o próprio LSO, núcleo do corpo trapezóide, o lemnisco lateral e seus núcleos, colículos inferior e superior e os seguintes núcleos talâmicos: suprageniculado, geniculado medial, partes dorsal e medial e córtex somatosensorial primário. Seguindo a via descendente contralateral nós encontramos as seguintes estruturas: o LSO ipsi e contralateral...

Função da neurotransmissão noradrenérgica do núcleo medial da amígdala na modulação do sistema cardiovascular em ratos; Noradrenergic neurotransmission function of the medial nucleus of the amygdala in the modulation of the cardiovascular system in rats.

Fortaleza, Eduardo Albino Trindade
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 21/03/2013 PT
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RESUMO FORTALEZA, E. A. T. Função da neurotransmissão noradrenérgica do núcleo medial da amígdala na modulação do sistema cardiovascular em ratos. 2013. 153p. Tese (Doutorado) Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, 2013. O núcleo medial da amígdala (NMA) está envolvido no controle de uma variedade de processos fisiológicos e comportamentais, dentre eles, a regulação do sistema cardiovascular durante situações aversivas. Além disso, existem evidências indicando a presença de receptores noradrenérgicos no NMA e que os níveis de noradrenalina (NA) no NMA aumentam quando animais são submetidos ao modelo de estresse por restrição (ER). Portanto, o presente estudo foi dividido em duas partes: 1) avaliamos os efeitos da microinjeção local de NA no NMA de ratos, bem como os receptores locais e os mecanismos periféricos envolvidos na sua mediação e 2) investigamos o papel desempenhado pela neurotransmissão noradrenérgica do NMA sobre as respostas cardiovasculares causadas pelo ER. A primeira parte dos nossos resultados indicou que doses crescentes de NA (3, 9, 27 ou 45nmol/100nL) microinjetadas no NMA causavam respostas pressoras e bradicardicas de maneira dose-dependente em ratos não anestesiados. Os efeitos da NA no NMA foram abolidos pelo pré-tratamento local com antagonista de receptores 2-adrenérgicos (RX821002...

Macrophage migration inhibitory factor in the nucleus of solitary tract decreases blood pressure in SHRs

Freiria-Oliveira, André Henrique; Blanch, Graziela Torres; Li, Hongwei; Colombari, Eduardo; Colombari, Débora Simões Almeida; Sumners, Colin
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 153-160
ENG
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Aims The macrophage migration inhibitory factor (MIF) is an intracellular inhibitor of the central nervous system actions of angiotensin II on blood pressure. Considering that angiotensin II actions at the nucleus of the solitary tract are important for the maintenance of hypertension in spontaneously hypertensive rats (SHRs), we tested if increased MIF expression in the nucleus of the solitary tract of SHR alters the baseline high blood pressure in these rats.Methods and resultsEight-week-old SHRs or normotensive rats were microinjected with the vector AAV2-CBA-MIF into the nucleus of the solitary tract, resulting in MIF expression predominantly in neurons. Rats also underwent recordings of the mean arterial blood pressure (MAP) and heart rate (via telemetry devices implanted in the abdominal aorta), cardiac- and baroreflex function. Injections of AAV2-CBA-MIF into the nucleus of the solitary tract of SHRs produced significant decreases in the MAP, ranging from 10 to 20 mmHg, compared with age-matched SHRs that had received identical microinjections of the control vector AAV2-CBA-eGFP. This lowered MAP in SHRs was maintained through the end of the experiment at 31 days, and was associated with an improvement in baroreflex function to values observed in normotensive rats. In contrast to SHRs...

Inhibitory mechanism of the nucleus of the solitary tract involved in the control of cardiovascular, dipsogenic, hormonal, and renal responses to hyperosmolality

Blanch, Graziela T.; Freiria-Oliveira, André H.; Murphy, David; Paulin, Renata F.; Antunes-Rodrigues, José; Colombari, Eduardo; Menani, Jose Vanderlei; Colombari, Débora S.A.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
ENG
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36.42%
The nucleus of the solitary tract (NTS) is the primary site of visceral afferents to the central nervous system. In the present study, we investigated the effects of lesions in the commissural portion of the NTS (commNTS) on the activity of vasopressinergic neurons in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei, plasma vasopressin, arterial pressure, water intake, and sodium excretion in rats with plasma hyperosmolality produced by intragastric 2 M NaCl (2 ml/rat). Male Holtzman rats with 15-20 days of sham or electrolytic lesion (1 mA; 10 s) of the commNTS were used. CommNTS lesions enhanced a 2 M NaCl intragastrically induced increase in the number of vasopressinergic neurons expressing c-Fos in the PVN (28 ± 1, vs. sham: 22 ± 2 c-Fos/AVP cells) and SON (26 ± 4, vs. sham: 11 ± 1 c-Fos/AVP cells), plasma vasopressin levels (21 ± 8, vs. sham: 6.6 ± 1.3 pg/ml), pressor responses (25 ± 7 mmHg, vs. sham: 7 ± 2 mmHg), water intake (17.5 ± 0.8, vs. sham: 11.2 ± 1.8 ml/2 h), and natriuresis (4.9 ± 0.8, vs. sham: 1.4 ± 0.3 meq/1 h). The pretreatment with vasopressin antagonist abolished the pressor response to intragastric 2 M NaCl in commNTS-lesioned rats (8 ± 2.4 mmHg at 10 min), suggesting that this response is dependent on vasopressin secretion. The results suggest that inhibitory mechanisms dependent on commNTS act to limit or counterbalance behavioral...

The effect of different defects and hydrogels for nucleus replacements on the biomechanical response of the intervertebral disc; conferenceObject

Reitmaier, Sandra; Wolfram, U.; Wilke, Hans-Joachim; Ignatius, Anita; Correia, Joana Silva; Oliveira, Joaquim M.; Reis, R. L.; Schmidt, Hendrik
Fonte: Wiley & Sons, Inc. Publicador: Wiley & Sons, Inc.
Tipo: Conferência ou Objeto de Conferência
Publicado em /09/2012 ENG
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Publicado em "Journal of Tissue Engineering and Regenerative Medicine", vol. 7, supp. 1 (2013); Hydrogels offer unique opportunities for regenerative strategies of the intervertebral disc. A nucleotomy necessary for the implantation of hydrogels, however, disrupts the annulus integrity and destroys natural interfaces in the disc. To clarify whether hydrogels can restore the mechanical competence of the disc an experimental testwas used. Intradiscal pressure(IDP) in an ovine disc was measured in vivo for 24 h and adapted to an axial compressive test consisting of three cycles 15-min diurnal and 30-min night load. To study the fluid mechanics, 30 motion segments in different defect conditions were used: (i) INTACT; (ii) DEFANN: isolated annulus defect; (iii) DEF-NUC: re-implanted nucleus; (iv) DDAHA and (v) iGG-MA: two hydrogels. DEF-ANN showed no significant difference in disc height loss or IDP compared to INTACT, while DEF-NUC reduced the IDP by ~30%(p = 0.03) and tended to increase the height loss(p = 0.2). Both DDAHA and iGG-MA better reflected the height loss of INTACT, but caused an even stronger loss in IDP than DEF-NUC(~34%). Neither the hydrogels nor the re-implanted nucleus, assumed to be the ideal implant...

Soft biomaterials as a substitute for the Nucleus Pulposus

Nabais, João António Pires Miranda
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Dissertação de Mestrado
Publicado em /09/2014 ENG
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One of the largest health problems faced worldwide, when evaluated by direct (clinical) as well indirect cost (absenteeism), is the degeneration of the intervertebral disc (IVD) that leads to back pain and, potentially disability and individual´s quality of life decreasing. The intervertebral disc is a mechanical and biological complex structure, formed by a tough outer layer of fibrocartilage called Annulus Fibrosus (AF),which surrounds a soft, elastic and gelatinous core called Nucleus Pulposus (NP). These two structures are completed by two upper and lower encasing layer called Vertebral Endplates (VEP). The degeneration of the IVD is marked by the dehydration of the Nucleus Pulposus, reducing the hydrostatic pressure inside the nucleus, resulting in a loss of capability to support compressive forces, during the active period, and to regain height during the resting period. This situation will compromise the role of shock absorber by the NP and transfers these forces to the AF. This transfer will result in cracks on the AF, deteriorating the IVD, allowing the ingrowth of vessels and nerves. This project was based on the developing a protocol to test suitable NP replacements, in hope to future assessment of discrete mechanical values and characteristics for an NP replacement. For this...

Ultrastructural transneuronal degeneration study of axonal elements within the paratrigeminal nucleus in sinoaortic deafferented rats

Caous,Cristofer André; Smith,Ricardo Luís; Haapalainen,Edna Freymuller; Lindsey,Charles Julian
Fonte: Instituto Israelita de Ensino e Pesquisa Albert Einstein Publicador: Instituto Israelita de Ensino e Pesquisa Albert Einstein
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 EN
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OBJECTIVE: Morphological study that searched to authenticate the presence of sinoaortic baroreceptor inputs within the dorsolateral medullary nucleus under electron microscopy analysis. METHODS: After a 5-day survival period, 9 baroreceptor-denervated rats deeply anaesthetized with equithesin were transcardially perfused and their brains were histologically processed. RESULTS: The neuronal cytoarchitecture of the paratrigeminal nucleus comprehends afferent projections from other nuclei that have a distributive character regarding visceral and nociceptive functions in the cardiovascular reflex integration response. CONCLUSION: The medial portion of the nucleus receives afferent projections of the rostral ventrolateral medulla, as shown by retrograde neurotracing studies. The present results show that the medial extent of the paratrigeminal nucleus contains degenerated axoplasmic cellular components in sinoaortic deafferented rats. The number of degenerated axonal fibers was also larger in this area of the nucleus.

Direct measurement of the transfer rate of chloroplast DNA into the nucleus

Huang, C.; Ayliffe, M.; Timmis, J.
Fonte: MacMillan Publishers Ltd Publicador: MacMillan Publishers Ltd
Tipo: Artigo de Revista Científica
Publicado em //2003 EN
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Gene transfer from the chloroplast to the nucleus has occurred over evolutionary time. Functional gene establishment in the nucleus is rare, but DNA transfer without functionality is presumably more frequent. Here, we measured directly the transfer rate of chloroplast DNA (cpDNA) into the nucleus of tobacco plants (Nicotiana tabacum). To visualize this process, a nucleus-specific neomycin phosphotransferase gene (neoSTLS2) was integrated into the chloroplast genome, and the transfer of cpDNA to the nucleus was detected by screening for kanamycin-resistant seedlings in progeny. A screen for kanamycin-resistant seedlings was conducted with about 250,000 progeny produced by fertilization of wild-type females with pollen from plants containing cp-neoSTLS2. Sixteen plants of independent origin were identified and their progenies showed stable inheritance of neoSTLS2, characteristic of nuclear genes. Thus, we provide a quantitative estimate of one transposition event in about 16,000 pollen grains for the frequency of transfer of cpDNA to the nucleus. In addition to its evident role in organellar evolution, transposition of cpDNA to the nucleus in tobacco occurs at a rate that must have significant consequences for existing nuclear genes.; Chun Y. Huang...

Transfer of plastid DNA to the nucleus is elevated during male gametogenesis in tobacco

Sheppard, A.; Ayliffe, M.; Blatch, L.; Day, A.; Delaney, S.; Khairul-Fahmy, N.; Li, Y.; Madesis, P.; Pryor, A.; Timmis, J.
Fonte: Amer Soc Plant Physiologists Publicador: Amer Soc Plant Physiologists
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
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In eukaryotes, many genes were transferred to the nucleus from prokaryotic ancestors of the cytoplasmic organelles during endosymbiotic evolution. In plants, the transfer of genetic material from the plastid (chloroplast) and mitochondrion to the nucleus is a continuing process. The cellular location of a kanamycin resistance gene tailored for nuclear expression (35SneoSTLS2) was monitored in the progeny of reciprocal crosses of tobacco (Nicotiana tabacum) in which, at the start of the experiments, the reporter gene was confined either to the male or the female parental plastid genome. Among 146,000 progeny from crosses where the transplastomic parent was male, 13 transposition events were identified, whereas only one atypical transposition was identified in a screen of 273,000 transplastomic ovules. In a second experiment, a transplastomic β-glucuronidase reporter gene, tailored to be expressed only in the nucleus, showed frequent stochastic expression that was confined to the cytoplasm in the somatic cells of several plant tissues. This gene was stably transferred in two out of 98,000 seedlings derived from a male transplastomic line crossed with a female wild type. These data demonstrate relocation of plastid DNA to the nucleus in both somatic and gametophytic tissue and reveal a large elevation of the frequency of transposition in the male germline. The results suggest a new explanation for the occurrence of uniparental inheritance in eukaryotes.; Anna E. Sheppard...

Potential functional replacement of the plastidic acetyl-CoA carboxylase subunit (accD) gene by recent transfers to the nucleus in some angiosperm lineages

Rousseau, M.; Huang, X.; Higginson, E.; Ayliffe, M.; Day, A.; Timmis, J.
Fonte: Amer Soc Plant Physiologists Publicador: Amer Soc Plant Physiologists
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
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36.34%
Eukaryotic cells originated when an ancestor of the nucleated cell engulfed bacterial endosymbionts that gradually evolved into the mitochondrion and the chloroplast. Soon after these endosymbiotic events, thousands of ancestral prokaryotic genes were functionally transferred from the endosymbionts to the nucleus. This process of functional gene relocation, now rare in eukaryotes, continues in angiosperms. In this article, we show that the chloroplastic acetyl-CoA carboxylase subunit (accD) gene that is present in the plastome of most angiosperms has been functionally relocated to the nucleus in the Campanulaceae. Surprisingly, the nucleus-encoded accD transcript is considerably smaller than the plastidic version, consisting of little more than the carboxylase domain of the plastidic accD gene fused to a coding region encoding a plastid targeting peptide. We verified experimentally the presence of a chloroplastic transit peptide by showing that the product of the nuclear accD fused to green fluorescent protein was imported in the chloroplasts. The nuclear gene regulatory elements that enabled the erstwhile plastidic gene to become functional in the nuclear genome were identified, and the evolution of the intronic and exonic sequences in the nucleus is described. Relocation and truncation of the accD gene is a remarkable example of the processes underpinning endosymbiotic evolution.; Mathieu Rousseau-Gueutin...

Modulation der Aktivität der Basalganglien im Parkinson-Modell der Ratte sowie nach Läsion des Nucleus pedunculopontinus; Modulation of the activity of the basal ganglia in the rat after 6-hydroxydopamine lesion of the substantia nigra pars compacta and after ibotenic acid lesion of the pedunculopontine nucleus

Leßmann, Linda Maria
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
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In dieser Arbeit wurden mit Hilfe von extrazellulärer in vivo Einzelzellableitung die Aktivitätsänderungen in den Basalganglien nach Läsion der Substantia nigra pars compacta und des Nucleus pedunculopontinus untersucht. Ziel hierbei war, einen genaueren Einblick in die Bedeutung des PPN für die Aktivität der Basalganglien zu erhalten und Hinweise dafür zu finden, ob die nach PPN-Läsion beim Primaten auftretende Akinese auf den gleichen pathophysiologischen Veränderungen beruht wie die Parkinson-Symptomatik nach dopaminergem Zellverlust in der SNc. Nach Läsion des PPN konnte eine Hyperaktivität von STN sowie GP festgestellt werden. Derartige Aktivitätsänderungen sind auch nach SNc-Läsion zu beobachten. Dies lässt vermuten, dass die nach PPN-Läsion beobachtete Akinese mit der Akinese im Rahmen eines Parkinson-Syndroms in pathophysiologischem Zusammenhang steht. Eine gemeinsame Ursache der Bewegungsstörung könnte in der Aktivitätsreduktion der dopaminergen Neurone der SNc liegen, welche nach Läsion des PPN durch den Wegfall der exzitatorischen Verbindungen von PPN zu SNc eine Situation vergleichbar der nach SNc-Läsion hervorrufen könnte. Nach SNc-Läsion zeigte sich in Übereinstimmung mit den Ergebnissen anderer Studien eine deutliche Hyperaktivität des STN. Im Widerspruch zu anderen Studien steht jedoch die hier aufgetretene Hyperaktivität des GP. So wäre die Ursache der STN-Hyperaktivität nicht wie häufig postuliert in einer GP-Hypoaktivität sondern in Aktivitätsänderungen von beispielsweise Thalamus...

Localization of insulin-like immunoreactive neurons in the rat gracile nucleus

Dheen, S.T.; Tay, S.S.W.; Wong, W. C.
Fonte: Murcia : F. Hernández Publicador: Murcia : F. Hernández
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
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An insulin-like immunoreactivity (ILIR) was localized in the neuronal somata, dendrites and myelinated axons in the gracile nucleus of the male Wistar rat. In the neuronal somata, the reaction product was dispersed in the cell nucleus and cytoplasm. In the cell nucleus, the reaction product was scattered throughout the nucleoplasm, but not within the nucleolus. In the cytoplasm, the reaction product was evenly distributed, mainly in the vicinity of the cistemae of the rough endoplasmic reticulum. In labelled dendrites, the reaction product was closely associated with the parallel arrays of neurotubules and postsynaptic densities. Most of these labelled dendrites were postsynaptic to unlabelled axon terminals. A labelled dendrite often formed the central element of a synaptic glomerulus with several unlabelled axon terminals. Numerous labelled myelinated axons were also present in the neuropil. However, axon terminals appeared to be unlabelled. It is hypothesized that insulin-like substance(s) may be modulating nuclear activities as well as neurotransmission at the synapse in the gracile nucleus.