The Edinger-Westphal nucleus II: Hypothalamic afferents in the rat

Numerous functions have been attributed to the Edinger-Westphal nucleus (EW), including those related to feeding behavior, pain control, alcohol consumption and the stress response. The EW is thought to consist of two parts: one controls accommodation, choroidal blood flow and pupillary constriction, primarily comprising cholinergic cells and projecting to the ciliary ganglion; and the other would be involved in the non-ocular functions mentioned above, comprising peptide-producing neurons and projecting to the brainstem, spinal cord and prosencephalic regions. Despite the fact that the EW is well known, its connections have yet to be described in detail. The aim of this work was to produce a map of the hypothalamic sources of afferents to the EW in the rat. We injected the retrograde tracer Fluoro-Gold into the EW, and using biotinylated dextran amine, injected into afferent sources as the anterograde control. We found retrogradely labeled cells in the following regions: subfornical organ, paraventricular hypothalamic nucleus, arcuate nucleus, lateral hypothalamic area, zona incerta, posterior hypothalamic nucleus, medial vestibular nucleus and cerebellar interpositus nucleus. After injecting BDA into the paraventricular hypothalamic nucleus, lateral hypothalamic area and posterior hypothalamic nucleus, we found anterogradely labeled fibers in close apposition to and potential synaptic contact with urocortin 1-immunoreactive cells in the EW. On the basis of our findings, we can suggest that the connections between the EW and the hypothalamic nuclei are involved in controlling stress responses and feeding behavior. © 2013 The Authors.

Investigation of the hypothalamic defensive system in the mouse

The hypothalamus plays especially important roles in various endocrine, autonomic, and behavioral responses that guarantee the survival of both the individual and the species. In the rat, a distinct hypothalamic defensive circuit has been defined as critical for integrating predatory threats, raising an important question as to whether this concept could be applied to other prey species. To start addressing this matter, in the present study, we investigated, in another prey species (the mouse), the pattern of hypothalamic Fos immunoreactivity in response to exposure to a predator (a rat, using the Rat Exposure Test). During rat exposure, mice remained concealed in the home chamber for a longer period of time and increased freezing and risk assessment activity. We were able to show that the mouse and the rat present a similar pattern of hypothalamic activation in response to a predator. of particular note, similar to what has been described for the rat, we observed in the mouse that predator exposure induces a striking activation in the elements of the medial hypothalamic defensive system, namely, the anterior hypothalamic nucleus, the dorsomedial part of the ventromedial hypothalamic nucleus and the dorsal premammillary nucleus. Moreover, as described for the rat, predator-exposed mice also presented increased Fos levels in the autonomic and parvicellular parts of the paraventricular hypothalamic nucleus, lateral preoptic area and subfornical region of the lateral hypothalamic area. In conclusion, the present data give further support to the concept that a specific hypothalamic defensive circuit should be preserved across different prey species. (C) 2008 Elsevier B.V. All rights reserved.

Hypothalamic supraoptic but not paraventricular nucleus is involved in cardiovascular responses to carbachol microinjected into the bed nucleus of stria terminalis of unanesthetized rats

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

Evidence of reciprocal connections between the dorsal raphe nucleus and the retina in the monkey Cebus apella

Possible connections between the retina and the raphe nuclei were investigated in the monkey Cebus apella by intraocular injection of cholera toxin B subunit (CTb). CTb-positive fibers were seen in the lateral region of the dorsal raphe nucleus (DR) on the side contralateral to the injection, and a few labeled perikarya were observed in the lateral portion of the DR on the ipsilateral side. Our findings suggest that direct and reciprocal connections between the retina and DR may exist in Cebus apella. These connections might be part of an important pathway through which the light/dark cycle influences the Activity and/or functional status of raphe neurons, with potential effects on a broad set of neural and behavioral circuits. (c) 2007 Elsevier B.V. All rights reserved.

Salivary cortisol to assess the hypothalamic-pituItary-adrenal axis in healthy children under 3 years old

Objective: To establish reference concentration intervals for salivary cortisol in healthy children, in the morning and in the afternoon, investigating factors that interfere with the concentration measured and the possibility that circadian rhythms are present.Methods: A controlled observational study was carried out with 91 children aged 45 days to 36 months, selected at random and living in Santo Andre, state of São Paulo, Brazil. Inclusion criteria were: healthy, well-nourished, free from fever and corticoid use, subdivided by age group (five subsets) at 6-month intervals. Saliva was collected during home visits in the morning and afternoon. Cortisol was radioimmunoassayed with cortisol 3-oxime-bovine albumin antiserum.Results: the five subsets exhibited higher cortisol concentration during the morning than in the afternoon (p < 0.001), and this difference passed 30% from 1 year of age onwards. Mean concentrations, in nmol/L, were 557.86 (morning) and 346.36 (afternoon). A negative linear correlation was observed between morning concentrations and hours' sleep and frequency of meals (p < 0,05), and in the afternoon with anthropometric measurements (p < 0.05).Conclusions: Reference values for normal salivary cortisol in healthy children were established. At:45 days it was possible to observe circadian rhythms, which reached maturity at 12 months of life. Sleep and food deprivation increased morning cortisol levels.

Photoelastic Analysis of Cemented or Screwed Implant-Supported Prostheses With Different Prostheses Connections

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

Biomechanical evaluation of internal and external hexagon platform switched implant-abutment connections: An in vitro laboratory and three-dimensional finite element analysis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Photoelastic Analysis of Biomechanical Behavior of Single and Multiple Fixed Partial Prostheses With Different Prosthetic Connections

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

Participation of alpha-1 and alpha-2 adrenoceptors of the lateral hypothalamic area in water intake, and renal sodium, potassium and urinary Volume excretion induced by central administration of angiotensin II

The circumventricular structures and the lateral hypothalamus (LH) have been shown to be important for the central action of angiotensin II (ANGII) on water and electrolyte regulation. Several anatomical findings have demonstrated neural connection between circumventricular structures and the LH, the present experiments were conducted to investigate the role of the alpha-adrenergic antagonists and agonistic injected into the LH on the water intake, sodium and potassium excretion elicited by injections of ANGII into the lateral ventricle (LV), the water intake was measured every 30 min over a period of 120 min. The sodium, potassium and urinary volume were measured over a period of 120 min in water-loaded rats. The injection of ANGII into the LV increased the water intake, which was reduced by previous injection of clonidine (an alpha-2-adrenergic agonist) into the LH. The injection of yohimbine (an alpha-2-adrenergic antagonist) and prazosin (an alpha-l-adrenergic antagonist) into the LH, which was done before injecting ANGII into the LV, also reduced the water intake induced by ANGII. The injection of ANGII into the LV reduced the sodium, potassium and urinary volume. Previous treatment with clonidine attenuated the action of ANGII in reducing the sodium, potassium and urinary volume, whereas previous treatment with yohimbine attenuated the effects of ANGII but with less intensity than that caused by clonidine. Previous treatment with prazosin increased the inhibitory effects of ANGII in those parameters. The injection of yohimbine and prazosin, which was done before the injection of clonidine, attenuated the effect of clonidine on the ANGII mechanism. The results of this study led us to postulate that when alpha-2-adrenergic receptors are blocked, the clonidine may act on the imidazoline receptors to produce its effects on the ANGII mechanism. We may also conclude that the LH is involved with circumventricular structures, which present excitatory and inhibitory mechanisms. Such mechanisms are responsible for regulating the renal excretion of sodium, potassium and water, (C) 2000 Elsevier B.V.

Endogenous hydrogen peroxide in the hypothalamic paraventricular nucleus regulates sympathetic nerve activity responses to L-glutamate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Hypothalamic disconnection caudal to paraventricular nucleus affects cardiovascular and drinking responses to central angiotensin II and carbachol

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

The sympathetic adrenomedullary system, but not the hypothalamic-pituitary-adrenal axis, participates in aorta adaptive response to stress: nitric oxide involvement

Stress induced a decrease in the reactivity of the aorta to noradrenaline (NA), as a consequence of an endothelial nitric oxide (NO) system hyperactivity. The main characteristic of the stress response is activation of the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic adrenomedullary (SA) system. The participation of the HPA axis and SA system in the decreased reactivity to NA in the aorta of rats exposed to 4-h immobilization was investigated. Concentration-response relationships for NA were obtained in the aorta, with and without endothelium, isolated from normal and stressed rats, following these procedures: (1) in the absence and presence of L-NAME; (2) after adrenalectomy (ADX) or not, in the absence or presence of L-NAME; (3) ADX rats treated or not with corticosterone; (4) ADX associated with stress; and (5) treated or not with reserpine. The reactivity of aorta without endothelium was unaffected by the procedures. The reactivity of aorta with endothelium was decreased by either stress or ADX. This effect was reversed by both L-NAME and corticosterone. ADX did not potentiate the decrease in the aorta reactivity induced by stress. Reserpine did not change the reactivity of aorta with endothelium from normal rats, but prevented the decrease in reactivity induced by stress. It is concluded that the HPA axis participates in endothelium-dependent modulation of aorta reactivity in normal conditions and that thr SA system participates in hyperactivity of the endothelial NO-system induced by stress, which is responsible for the decreased aorta reactivity to NA. (C) 2000 Elsevier B.V. B.V. All rights reserved.