Ultramorphology and histology of dorsal vessel - Gastral portion - Of Camponotus rufipes

The dorsal diaphragm of Camponotus rufipes (Hymenoptera: Formicidae) is a thin membrane structure, with free edges between the points of attachment to the body wall that almost cover the whole extension of the dorsal vessel at its abdominal portion. A layer of fat body cells covers the region of the cuticle above the dorsal vessel and the incurrent ostia can be a vertical or horizontal slit in the wall of the heart. One organized structure as a network ofalary muscles was observed holding the heart at its middorsal position and supporting the pericardial cells too. A great number of pericardial cells were found laterally associated with the heart and cellular projections from those cells insert directly into the heart wall.

Histologia e ultra-estrutura do vaso dorsal de Scaptotrigona postica (Hymenoptera, Apidae) em operárias e rainhas de diferentes idades

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

Histology and ultrastructure of pericardial cells of Scaptotrigona postica latreille (Hymenoptera, Apidae) in workers and queens of different ages

The paper presents a study of the pericardial cells of Scaptotrigona postica an eusocial Brazilian stingless bee. Light and electron microscopy was used in a comparative study on workers and queens of different ages, exerting different functions in the colony. The pericardial cells are found only in the peticardial sinus, mainly in groups around the dorsal vessel. Each cell is enclosed by the basal membrane and its peripheral region is characterized by folds of the plasma membrane, which form canals and loops. The points where the plasma membrane folds is frequently closed by diaphragms, that along with the basal lamina form a barrier to substances from hemolymph. Along the membrane limiting the canals and loops, an intense endocytic activity through coated vesicles takes place indicating a selective absorption of hemolymph components. In older individuals, workers or queens, the cells exhibit larger quantities of cytoplasm inclusions, heterogeneous vacuoles containing the final products of intracellular digestion, and autophagic vacuoles with concentric membranous structures. The pericardial cells general morphology is in accordance with the role in processing metabolites captured from hemolymph and storage of indigested residues. (C) 2006 Elsevier Ltd. All rights reserved.

Intraoperative topical administration of mitomycin C, in different concentrations, on the cicatrization of mioplasties of the dorsal rectus of rabbits

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

Evaluation of the Integrity of Horse Hoof Dermal and Epidermal Tissues Collected by Dorsal Transmural Access

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The dorsal raphe nucleus exerts opposed control on generalized anxiety and panic-related defensive responses in rats

It has been proposed that the ascending dorsal raphe (DR)-serotonergic (5-HT) pathway facilitates conditioned avoidance responses to potential or distal threat, while the DR-periventricular 5-HT pathway inhibits unconditioned flight reactions to proximal danger. Dysfunction on these pathways would be, respectively, related to generalized anxiety (GAD) and panic disorder (PD). To investigate this hypothesis, we microinjected into the rat DR the benzodiazepine inverse receptor agonist FG 7142, the 5-HT1A receptor agonist 8-OH-DPAT or the GABA(A) receptor agonist muscimol. Animals were evaluated in the elevated T-maze (ETM) and light/dark transition test. These models generate defensive responses that have been related to GAD and PD. Experiments were also conducted in the ETM 14 days after the selective lesion of DR serotonergic neurons by 5,7-dihydroxytriptamine (DHT). In all cases, rats were pre-exposed to one of the open arms of the ETM 1 day before testing. The results showed that FG 7142 facilitated inhibitory avoidance, an anxiogenic effect, while impairing one-way escape, an anxiolytic effect. 8-OH-DPAT, muscimol, and 5,7-DHT-induced lesions acted in the opposite direction, impairing inhibitory avoidance while facilitating one-way escape from the open arm. In the light/dark transition, 8-OH-DPAT and muscimol increased the time spent in the lighted compartment, an anxiolytic effect. The data supports the view that distinct DR-5-HT pathways regulate neural mechanisms underlying GAD and PD. (C) 2002 Elsevier B.V. B.V. All rights reserved.

5-HT1A receptors in the dorsal hippocampus mediate the anxiogenic effect induced by the stimulation of 5-HT neurons in the median raphe nucleus

We evaluated the involvement of dorsal hippocampus (DH) 5-HT1A receptors in the mediation of the behavioral effects caused by the pharmacological manipulation of 5-HT neurons in the median raphe nucleus (MRN). To this end, we used the rat elevated T-maze test of anxiety. The results showed that intra-DH injection of the 5-HT1A/7 agonist 8-OH-DPAT facilitated inhibitory avoidance, an anxiogenic effect, without affecting escape. Microinjection of the 5-HT1A antagonist WAY-100635 was ineffective. In the elevated T-maze, inhibitory avoidance and escape have been related to generalized anxiety and panic disorders, respectively. Intra-MRN administration of the excitatory aminoacid kainic acid, which non-selectively stimulates 5-HT neurons in this brain area facilitated inhibitory avoidance and impaired escape performance, but also affected locomotion. Intra-MRN injection of WAY-100635, which has a disinhibitory effect on the activity of 5-HT neurons in this midbrain area, only facilitated inhibitory avoidance. Preadministration of WAY-100635 into the DH blocked the behavioral effect of intra-MRN injection of WAY-100635, but not of kainic acid. These results indicate that DH 5-HT1A receptors mediate the anxiogenic effect induced by the selective stimulation of 5-HT neurons in the MRN. (c) 2007 Elsevier B.V. and ECNP. All rights reserved.

Physical environment modulates the behavioral responses induced by chemical stimulation of dorsal periaqueductal gray in mice

In order to investigate the relationship between behaviors elicited by chemical stimulation of the dorsal periaqueductal gray (dorsal PAG) and spontaneous defensive behaviors to a predator, the excitatory amino acid D,L-homocysteic acid (5 nmol in 0.1 mu l), was infused into the dorsal PAG and behavioral responses of mice were evaluated in two different situations, a rectangular novel chamber or the Mouse Defense Test Battery (MDTB) apparatus. During a 1-min period following drug infusion, more jumps were made in the chamber than in the MDTB runway but running time and distance traveled were significantly higher in the runway. Animals were subsequently tested using the standard MDTB procedure (anti-predator avoidance, chase and defensive threat/attack). No drug effects on these measures were significant. In a further test in the MDTB apparatus, the pathway of the mouse during peak locomotion response was blocked 3 times by the predator stimulus (anesthetized rat) to determine if the mouse would avoid contact. Ninety percent of D,L-homocysteic treated animals made direct contact with the stimulus (rat), indicating that D,L-homocysteic-induced running is not guided by relevant (here, threat) stimuli. These results indicate that running as opposed to jumping is the primary response in mice injected with D,L-homocysteic into the dorsal PAG when the environment enables flight. However, the lack of responsivity to the predator during peak locomotion suggests that D,L-homocysteic-stimulation into the dorsal PAG does not induce normal antipredator flight. (c) 2006 Published by Elsevier B.V.

Anxiogenic-like effects of mCPP microinfusions into the amygdala (but not dorsal or ventral hippocampus) in mice exposed to elevated plus-maze

Serotonin (5-HT) can either increase or decrease anxiety-like behaviour in animals, actions that depend upon neuroanatomical site of action and 5-HT receptor subtype. Although systemic studies with 5-HT(2) receptor agonists and antagonists suggest a facilitatory role for this receptor subtype in anxiety, somewhat inconsistent results have been obtained when such compounds have been directly applied to limbic targets such as the hippocampus and amygdala. The present study investigated the effects of the 5-HT(2B/2C) receptor agonist mCPP bilaterally microinjected into the dorsal hippocampus (DH: 0, 0.3 1.0 or 3.0 nmol/0.2 mu l), the ventral hippocampus (VH: 0, 0.3, 1.0 or 3.0 nmol/0.2 mu l) or the amygdaloid complex (0, 0.15, 0.5, 1.0 or 3.0 nmol/0.1 mu l) in mice exposed to the elevated plus-maze (EPM). Test sessions were videotaped and subsequently scored for conventional indices of anxiety (percentage of open arm entries and percentage of open arm time) and locomotor activity (closed arm entries). Results showed that mCPP microinfusions into the DH or VH failed to affect any behavioural measure in the EPM. However, when injected into the amygdaloid complex, the dose of 1.0 nmol of this 5HT(2B/2C) receptor agonist increased behavioural indices of anxiety without significantly altering general activity levels. This anxiogenic-like effect of mCPP was selectively and completely blocked by local injection of a behaviourally-inactive dose of SDZ SER-082 (10 nmol/0.1 mu l), a preferential 5-HT(2C) receptor antagonist. These data suggest that 5HT(2C) receptors located within the amygdaloid complex (but not the dorsal or ventral hippocampus) play a facilitatory role in plus-maze anxiety in mice. (c) 2007 Elsevier B.V. All rights reserved.

Anxiolytic-like effect of way-100635 microinfusions into the median (but not dorsal) raphe nucleus in mice exposed to the plus-maze: influence of prior test experience

Studies in several laboratories have confirmed the anxiolytic potential of a wide range of 5-HT1A receptor antagonists in rats and mice, with recent evidence pointing to a postsynaptic site of action in the ventral hippocampus. It would, therefore, be predicted that blockade of 5-HT1A somatodendritic autoreceptors in the midbrain raphe nuclei should produce anxiogenic-like effects. To test this hypothesis, we investigated the effects of WAY-100635 microinfusions (0, 1.0 or 3.0 mug in 0.1 mul) into the dorsal (DRN) or median (MRN) raphe nuclei on behaviours displayed by male Swiss-Webster mice in the elevated plus-maze. As this test is sensitive to prior experience. The effects of intra-raphe infusions were examined both in maze-naive and maze-experienced subjects. Sessions, were videotaped and subsequently scored for conventional indices of anxiety (open arm avoidance) and locomotor activity (closed arm entries), as well as a range of ethological measures (e.g. risk assessment). In maze-naive mice, intra-MRN (but not intra-DRN) infusions of WAY-100635 (3.0 mug) increased open arm exploration and reduced risk assessment. Importantly, these effects could not be attributed to a general reduction in locomotor activity. A similar, though somewhat weaker, pattern of behavioural change was observed in maze-experienced animals. This unexpected anxiolytic effect of 5-HT1A autoreceptor blockade in the MRN cannot be accounted fur by a disinhibition of 5-HT release in forebrain targets (e.g. hippocampus and amygdala), where stimulation of postsynaptic 5-HT1A receptors enhances anxiety-like responses. However, as the MRN also projects to the periaqueductal gray matter (PAG), an area known to be sensitive to the anti-aversive effects or 5-HT, it is argued that present results may reflect increased 5-HT release at this crucial midbrain locus within the neural circuitry of defense. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Activation of 5-HT2C receptors in the dorsal periaqueductal gray increases antinociception in mice exposed to the elevated plus-maze

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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.

Estudo mecânico da estabilidade dorsal da osteossíntese intramedular associada à fixação externa (método de Ulson)

OBJETIVO: Avaliar o método de Ulson de fixação intramedular associado à fixação externa variando a altura do travamento externo dos fios de Kirschner e sem fixação externa. MÉTODO: Foram utilizadas 18 tíbias de porcos, sendo realizada osteotomia transversal na região da tuberosidade e introduzidos dois fios de Kirschner intramedulares em cada peça, em três diferentes padrões de montagem: grupo I - travamento com minifixador externo com 3,0cm de altura; grupo II - travamento com 4,5cm de altura; grupo III: sem travamento externo. Realizaram-se ensaios mecânicos de cisalhamento, obtendo-se: carga máxima, limite de proporcionalidade e coeficiente de rigidez. RESULTADOS: Não foram encontradas diferenças significativas de carga máxima e limite de proporcionalidade entre os grupos; o grupo II apresentou maior coeficiente de rigidez. CONCLUSÃO: A altura do travamento dos fios de Kirschner no método de Ulson, dentro dos limites avaliados, não prejudicou a estabilidade do sistema de fixação da fratura.

Utilização de contrairritante no tratamento da fixação dorsal de patela intermitente em equinos: relato de casos

Em nove equinos atendidos por apresentarem fixação dorsal de patela intermitente, optou-se pela aplicação de 2mL de contrairritante na região subcutânea, ao longo dos ligamentos patelares medial e intermédio. No período de 12 a 48h após a aplicação, os animais apresentaram aumento de volume e de temperatura local, sensibilidade dolorosa à palpação e relutância à locomoção. Após esse período, os sinais clínicos de inflamação e fixação dorsal de patela foram gradativamente diminuindo até o sétimo dia, em sete dos nove animais avaliados. Após a remissão dos sinais de inflamação, dois animais não responderam ao tratamento, sendo necessária a repetição em um dos casos e realização de desmotomia patelar medial no outro. A aplicação de contrairritante foi eficaz na remissão do sinal clínico de fixação dorsal da patela intermitente. Comparativamente às técnicas cirúrgicas para a correção da enfermidade descritas na literatura, o tratamento promoveu melhora precoce dos sinais, curto período de convalescência e praticidade na realização.

Morphological and morphometric study of the opossum's dorsal root ganglia neurons

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.