Hypercapnic ventilatory response of anesthetized female rats subjected to neonatal maternal separation: Insight into the origins of panic attacks?

Neonatal maternal separation (NMS) is a form of stress that interferes with the regulation of the stress response, an effect that predisposes to the emergence of panic and anxiety related disorders. We previously showed that at adulthood, awake female (but not male) rats subjected to NMS show a hypercapnic ventilatory response (HCVR; 5% CO(2)) that is 63% greater than controls (Genest et al., 2007). To understand the mechanisms underlying the sex-specific effects of NMS on the ventilatory response to CO(2), we used two different anesthetized female rat preparations to assess central CO(2) chemosensitivity and contribution of sensory afferents (stretch receptors and peripheral chemoreceptors) that influence the HCVR. Data show that anesthesia eliminated the respiratory phenotype observed previously in awake females and CO(2) chemosensitivity did not differ between groups. Finally, the assessment of the ovarian hormone levels across the oestrus cycle failed to reveal significant differences between groups. Since anesthesia did not affect the manifestation of NMS-related respiratory dysfunction in males (including the hypercapnic ventilatory response) (Kinkead et al., 2005; Dumont and Kinkead, 2010), we propose that the panic or anxiety induced by CO(2) during wakefulness is responsible for enhancement of the HCVR in NMS females. (C) 2011 Elsevier B.V. All rights reserved.

Ionotropic glutamatergic receptors in the rostral medullary raphe modulate hypoxia and hypercapnia-induced hyperpnea

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

Opioid mu-receptors in the rostral medullary raphe modulate hypoxia-induced hyperpnea in unanesthetized rats

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

Experimental infection of Newcastle disease virus in pigeons (Columba livia): Humoral antibody response, contact transmission and viral genome shedding

The aim of this study was to evaluate the humoral antibody response, the genome viral excretion and the contact transmission of pathogenic chicken origin Newcastle disease virus (NDV) from experimentally infected pigeons (Columba livia) to in-contact pigeon. The antibody response to infection was assessed by the hemagglutination inhibition (HI) test and the genome viral excretion was detected by RT-PCR. Viral strain induced high antibody levels, both in inoculated and in sentinel birds. The pathogenic viral strain for chickens was unable to produce clinical signs of the disease in experimentally infected pigeons, although it induced the Immoral antibody response and produced NDV genome shedding. NDV genome was detected intermittently throughout the experimental period, from 5 days post-infection (dpi) to 24 dpi. Therefore, viral genome shedding occurred for 20 days. The viral genome was detected in all birds, between I I and 13 dpi. Furthermore, the high infectivity of the virus was confirmed, as all non-inoculated sentinel pigeons showed antibody levels as high as those of inoculated birds. (C) 2007 Elsevier B.V. All rights reserved.

Inflammation induced by inactivated Aeromonas hydrophila in Nile tilapia fed diets supplemented with Saccharomyces cerevisiae

The inflammatory response and hernatological parameters among Nile tilapia (Oreochromis niloticus) supplemented with Saccharomyces cerevisiae were evaluated six and 24 h after inoculation with inactivated Aeromonas hydrophila into the swim bladder. Six groups were formed (n = 10 each): G1 was treated with non-supplemented feed+injection with 0.65% saline solution; G2 with non-supplemented feed+ inoculation with A. hydrophila: G3 with feed containing 2% yeast+ injection with saline; G4 with feed containing 2% yeast + inoculation with A. hydrophila: G5 with feed containing 0.3% cell wall + injection with saline: and G6 with feed containing 0.3% cell wall + inoculation with A. hydrophila. In the groups inoculated with bacteria, the responses were more intense (P<0.05) than in those injected with saline. The groups receiving supplement that were inoculated with A. hydrophila accumulated a greater total number of cells at the lesion site (P<0.05) than did the non-supplemented groups, after six and 24 h. The groups receiving cell wall presented greater total accumulation of cells (P<0.005) that did those receiving yeast. The differential count showed that there were significantly greater number of thrombocytes (P< 0.05) and lower number of neutrophils, macrophages and lymphocytes (P<0.05) in the groups that received supplement, after 6 and 24 h, in relation to the non-supplemented groups. The values in the erythrocyte count, hemoglobin concentration and blood measurement indices did not differ statistically. The variation in circulating thrombocyte and leukocyte counts suggests that the inflammatory stimulus caused recruitment from reserve compartments to the blood. The groups that received yeast or yeast cell wall supplements presented increased nonspecific acute inflammatory response, thus suggesting that this has a beneficial effect on the immunological defense system. Published by Elsevier B.V.

Characterization of the acute inflammatory response in the hybrid tambacu (Piaractus mesopotamicus male × Colossoma macropomum female) (Osteichthyes)

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

Whole-genome expression profiling of Xylella fastidiosa in response to growth on glucose

Xylella fastidiosa is the etiologic agent of diseases in a wide range of economically important crops including citrus variegated chlorosis, a major threat to the Brazilian citrus industry. The genomes of several strains of this phytopathogen have been completely sequenced enabling large-scale functional studies. In this work we used whole-genome DNA microarrays to investigate the transcription profile of X. fastidiosa grown in defined media with different glucose concentrations. Our analysis revealed that while transcripts related to fastidian gum production were unaffected, colicin-V-like and fimbria precursors were induced in high glucose medium. Based on these results, we suggest a model for colicin-defense mechanism in X. fastidiosa.

Dominant follicle removal by ultrasound guided transvaginal aspiration and superovulatory response in Nellore cows

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

Behavior of Leishmania major metacyclic promastigotes during the course of infection and immune response development in resistant versus susceptible hosts

Pouco se conhece sobre os epítopos derivados de promastigotas metacíclicos de Leishmania que são importantes para a regulação ou destruição do parasita, como alvos de ação imunológica no hospedeiro vertebrado. Neste estudo, nós investigamos um método alternativo para obter promastigotas metacíclicos de Leishmania major, pela avaliação do curso da infecção e reação de hipersensibilidade do tipo retardado (HTR) em hospedeiros resistentes e susceptíveis. Promastigotas não-infectantes (procíclicos) de L. major, recentemente isolados de amastigotas, foram selecionados pela adesão a colunas de lã de vidro negativamente carregadas, enquanto que promastigotas metacíclicos não se aderem à coluna e podem ser recuperados com facilidade. Condições ótimas de cromatografia foram validadas por análise estatística. O rendimento médio de parasitas obtidos após separação em colunas de lã de vidro e a viabilidade dos promastigotas foram estimados por microscopia óptica. Os promastigotas metacíclicos tiveram um rendimento médio de 43,5% a 57,5%. Camundongos BALB/c (susceptíveis) e camundongos C57BL/6 (resistentes) apresentaram padrões distintos de lesões cutâneas, os primeiros com lesões mais agressivas, induzidas por promastigotas metacíclicos. As respostas à reação de HTR foram maiores nos grupos de camundongos C57BL/6, submetidos à infecção com promastigotas metacíclicos. Estes resultados indicam que o novo método poderia ser integrado aos protocolos existentes para estudar a metaciclogênese de parasitas do gênero Leishmania in vivo.

Role of Yersinia pseudotuberculosis outer proteins (Yops) in murine humoral immune response

The infection of mice with the wild-type (WT) strain of Y. pseudotuberculosis did not induce polyclonal activation of B lymphocytes. Suppression in the production of certain isotypes of Ig was observed, provoked mainly by YopH, YopJ and YpkA. The WT strain induced a progressive increase in the serum-specific IgG, which peaked after 4 weeks after infection, IgM being produced only after 1 week. Autoantibodies against phosphorylcholine, myelin, thyroglobulin and cardiolipin could be detected in the serum of mice infected with the WT strain. The infection of mice provoked suppression in the production of immunoglobulins by splenic B cells and that YopH, YopJ and YpkA must be involved here.

Cell cycle arrest evidence, parasiticidal and bactericidal properties induced by L-amino acid oxidase from Bothrops atrox snake venom

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

Anxiety-induced antinociception in mice: effects of systemic and intra-amygdala administration of 8-OH-DPAT and midazolam

Rationale: Mice exhibit antinociception after a single experience in the elevated plus maze (EPM), an animal model of anxiety. Objective: This study investigated the mechanisms involved in this form of anxiety-induced antinociception. Methods: Nociception was evaluated by means of the writhing test in mice confined either to the open or enclosed arms of the EPM. The effects of systemic (naloxone, midazolam and 8-OH-DPAT) or intra-amygdala (8-OH-DPAT. NAN-190 and midazolam) drug infusions were investigated in mice previously treated i.p. with 0.6% acetic acid, an algic stimulus that induces abdominal contortions. The effects of these drugs on conventional measures of anxiety (% entries and % time in open arms) in a standard EPM test were also independently investigated. Results: Open-arm confinement resulted in a high-magnitude antinociception (minimum 85%, maximum 450%) compared with enclosed arm confinement. The opiate antagonist naloxone (1 mg/kg and 10 mg/kg) neither blocked this open arm-induced antinociception (OAIA) nor modified indices of anxiety in EPM. Administration of midazolam (0.5-2 mg/kg, s.c.) increased OAIA and produced antinociception in enclosed confined animals, as well as attenuating anxiety in the EPM. The 5-HT(1A) receptor agonist 8-OH-DPAT (0.05-1 mg/kg, s.c.) had biphasic effects on OAIA, antagonising the response at the lowest dose and intensifying it at the highest dose. In addition, low doses of this agent reduced anxiety in the EPM. Although bilateral injections of 8-OH-DPAT (5.6 nmol/0.4 mu l) or NAN-190 (5.6 nmol and 10 nmol/0.4 mu l) into the amygdala did not alter OAIA, increased anxiety was observed in the EPM. In contrast, intra-amygdala administration of midazolam (10 nmol and 30 nmol/0.4 mu l) blocked both OAIA and anxiety. Conclusions: These results with systemic and intracerebral drug infusion suggest that 5-HT(1A) receptors localised in the amygdala are not involved in the pain inhibitory processes that are recruited during aversive situations. However, activation of these receptors does phasically increase anxiety. Although the intrinsic antinociceptive properties of systemically administered midazolam confounded interpretation of its effects on OAIA, intra-amygdala injections of this compound suggest that benzodiazepine receptors in this brain region modulate both the antinociceptive and behavioural (anxiety) responses to the EPM.

Defensive-like behaviors and antinociception induced by NMDA injection into the periaqueductal gray of mice depend on nitric oxide synthesis

Glutamate NMDA receptor activation within the periaqueductal gray (PAG) leads to antinociceptive, autonomic and behavioral responses characterized as the fear reaction. Considering that NMDA receptor triggers activation of neuronal nitric oxide synthase (nNOS), enzyme that produces nitric oxide (NO), this study investigated the effects of intra-PAG infusions of NPLA (N omega-propyl-L-arginine), an nNOS inhibitor, on behavioral and antinociceptive responses induced by local injection of NMDA receptor agonist in mice. The behaviors measured were frequency of jumping and rearing as well as duration (in seconds) of running and freezing. Nociception was assessed during the second phase of the formalin test (injection of 50 mu l of formalin 2.5% into the dorsal surface of the right hind paw). Five to seven days after stereotaxic surgery for intracerebral cannula implantation, mice were injected with formalin into the paw, and 10 min later, they received intra-dPAG injection of NPLA (0, 0.2, or 0.4 nmol/0.1 mu l). Ten minutes later, they were injected with NMDA (N-methyl-D-aspartate: 0 or 0.04 nmol/0.1 mu l) into the same midbrain site and were immediately placed in glass holding cage for recording the defensive behavior and the time spent on licking the injected paw with formalin during a period of 10 min. Microinjections of NMDA significantly decreased nociception response and produced jumping, running, and freezing reactions. Intra-dPAG injections of NPLA (0.4 nmol) completely blocked the NMDA effects without affecting either behavioral or nociceptive responses in intra-dPAG saline-injected animals, except for the rearing frequency that was increased by the nNOS inhibitor. These results strongly suggest the involvement of NO within the PAG in the antinociceptive and defensive reactions induced by local glutamate NMDA receptor activation in this midbrain structure. (c) 2006 Elsevier B.V. All rights reserved.

Influence of Th1/Th2 cytokines and nitric oxide in murine systemic infection induced by Sporothrix schenckii

In an attempt to elucidate the effects of Sporothrix schenckii infection on the immune response, our laboratory has developed a murine model of disseminated sporotrichosis. Helper T cells can be further subdivided into Th1 and Th2 phenotypes. The differentiation of two subsets of T lymphocytes is driven by IL-12 and IL-4 cytokines, respectively. Th1 cells produce IFN-gamma that activate macrophages and promote cell-mediated immunity. In addition, we found low levels of iNOS and NO production in the initial (1st and 2nd weeks) and final (9th and 10th weeks) periods of the infection, in contrast with the period of week 4 to 7 of elevated values. The determination of IFN-gamma and IL-12 are in agreement with NO/iNOS detection, showing the presence of cellular immune response throughout the infectious process. However, the production of IL-4 shows an increase in levels after the 5th and 6th weeks suggesting a participation of Th2 response in this period as well. Regarding these results, the study demonstrated that in experimental sporotrichosis infection the cellular immune response participated throughout the period analyzed as a nitric oxide dependent mechanism. In contrast, the presence of Th2 response began in the 5th week, suggesting the participation of humoral immune response in advanced stages of sporotrichosis.

Repeated predictable or unpredictable stress: effects on cocaine-induced locomotion and cyclic AMP-dependent protein kinase activity

Stressful experiences appear to have a strong influence on susceptibility to drug taking behavior. Cross-sensitization between stress and drug-induced locomotor response has been found. Locomotor response to novelty or cocaine (10 mg/kg, i.p.), cyclic AMP-dependent protein kinase (PKA) activity in the nucleus accumbens and basal corticosterone levels were evaluated in male adult rats exposed to acute and chronic predictable or unpredictable stress. Rats exposed to a 14-day predictable stress showed increased locomotor response to novelty and to cocaine, whereas rats exposed to chronic unpredictable stress demonstrated increased cyclic AMP-dependent PKA activity in the nucleus accumbens. Both predictable and unpredictable stress increased basal corticosterone plasma levels. These experiments demonstrated that stress-induced early cocaine sensitization depends on the stress regime and is apparently dissociated from stress-induced changes in cyclic AMP-dependent PKA activity and corticosterone levels. (C) 2002 Elsevier B.V. B.V. All rights reserved.