Autonomic control of heart rate during forced activity and digestion in the snake Boa constrictor

Reptiles, particularly snakes, exhibit large and quantitatively similar increments in metabolic rate during muscular exercise and following a meal, when they are apparently inactive. The cardiovascular responses are similar during these two states, but the underlying autonomic control of the heart remains unknown. We describe both adrenergic and cholinergic tonus on the heart during rest, during enforced activity and during digestion (24-36h after ingestion of 30% of their body mass) in the snake Boa constrictor. The snakes were equipped with an arterial catheter for measurements of blood pressure and heart rate, and autonomic tonus was determined following infusion of the beta -adrenergic antagonist propranolol (3mg kg(-1)) and the muscarinic cholinoceptor antagonist atropine (3 mg kg-1).The mean heart rate of fasting animals at rest was 26.4 +/- 1.4 min(-1), and this increased to 36.1 +/- 1.4 min(-1) (means +/- S.E.M.; N=8) following double autonomic block (atropine and propranolol). The calculated cholinergic and adrenergic tones were 60.1 +/- 0.3% and 19.8 +/- 2.2%, respectively. Heart rate increased to 61.4 +/- 1.5 min(-1) during enforced activity, and this response was significantly reduced by propranolol (maximum values of 35.8 +/-1.6 min(-1)), but unaffected by atropine. The cholinergic and adrenergic tones were 2.6 +/- 2.2 and 41.3 +/- 1.9 % during activity, respectively. Double autonomic block virtually abolished tachycardia associated with enforced activity (heart rate increased significantly from 36.1 +/- 1.4 to 37.6 +/- 1.3 min(-1)), indicating that non-adrenergic, non-cholinergic effectors are not involved in regulating heart rate during activity. Blood pressure also increased during activity.Digestion was accompanied by an increase in heart rate from 25.6 +/- 1.3 to 47.7 +/- 2.2 min(-1) (N=8). In these animals, heart rate decreased to 44.2 +/- 2.7 min-1 following propranolol infusion and increased to 53.9 +/- 1.8 min-1 after infusion of atropine, resulting in small cholinergic and adrenergic tones (6.0 +/- 3.5 and 11.1 +/- 1.1 %, respectively). The heart rate of digesting snakes was 47.0 +/- 1.0 min(-1) after double autonomic blockade, which is significantly higher than the value of 36.1 1.4 min-1 in double-blocked fasting animals at rest. Therefore, it appears that some other factor exerts a positive chronotropic effect during digestion, and we propose that this factor may be a circulating regulatory peptide, possibly liberated from the gastrointestinal system in response to the presence of food.

Pseudechis australis Venomics: Adaptation for a Defense against Microbial Pathogens and Recruitment of Body Transferrin

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

SINGULARITY THEORY and FORCED SYMMETRY BREAKING IN EQUATIONS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Loss of superfluidity in a Bose-Einstein condensate via forced resonant oscillations

We predict the loss of superfluidity in a Bose-Einstein condensate in an axially symmetric harmonic trap alone during resonant collective oscillations via a classical dynamical transition. The forced resonant oscillation can be initiated by (a) periodic modulation of the atomic scattering length with a frequency that equals twice the radial trapping frequency or multiples thereof, or by (b) periodic modulation of the radial trapping potential with a frequency that equals the radial trapping frequency or multiples thereof. Suggestion for future experiment is made. (C) 2003 Elsevier B.V. B.V. All rights reserved.

Influence of gender and estrous cycle in the forced swim test in rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fertility of male adult rats submitted to forced swimming stress

We investigated whether stress interferes with fertility during adulthood. Male Wistar rats (weighing 220 g in the beginning of the experiment) were forced to swim for 3 min in water at 32ºC daily for 15 days. Stress was assessed by the hot-plate test after the last stressing session. To assess fertility, control and stressed males (N = 15 per group) were mated with sexually mature normal females. Males were sacrificed after copulation. Stress caused by forced swimming was demonstrated by a significant increase in the latency of the pain response in the hot-plate test (14.6 ± 1.25 s for control males vs 26.0 ± 1.53 s for stressed males, P = 0.0004). No changes were observed in body weight, testicular weight, seminal vesicle weight, ventral prostate weight or gross histological features of the testes of stressed males. Similarly, no changes were observed in fertility rate, measured by counting live fetuses in the uterus of normal females mated with control and stressed males; no dead or incompletely developed fetuses were observed in the uterus of either group. In contrast, there was a statistically significant decrease in spermatid production demonstrated by histometric evaluation (154.96 ± 5.41 vs 127.02 ± 3.95 spermatids per tubular section for control and stressed rats, respectively, P = 0.001). These data demonstrate that 15 days of forced swimming stress applied to adult male rats did not impair fertility, but significantly decreased spermatid production. This suggests that the effect of stress on fertility should not be assessed before at least the time required for one cycle of spermatogenesis.

Female monopolization and paternity assurance in South American crickets (Orthoptera, Grylloidea): mating plugs, extra claspers and forced copulation

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

Forced convection to laminar flow of liquid egg yolk in circular and annular ducts

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

The Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders: recruitment, assessment instruments, methods for the development of multicenter collaborative studies and preliminary results

OBJETIVO: Descrever o recrutamento de pacientes, instrumentos de avaliação, métodos para o desenvolvimento de estudos colaborativos multicêntricos e os resultados preliminares do Consórcio Brasileiro de Pesquisa em Transtornos do Espectro Obsessivo-Compulsivo, que inclui sete centros universitários. MÉTODO: Este estudo transversal incluiu entrevistas semi-estruturadas (dados sociodemográficos, histórico médico e psiquiátrico, curso da doença e diagnósticos psiquiátricos comórbidos) e instrumentos que avaliam os sintomas do transtorno obsessivo-compulsivo (Escala para Sintomas Obsessivo-Compulsivos de Yale-Brown e Escala Dimensional para Sintomas Obsessivo-Compulsivos de Yale-Brown), sintomas depressivos (Inventário de Depressão de Beck), sintomas ansiosos (Inventário de Ansiedade de Beck), fenômenos sensoriais (Escala de Fenômenos Sensoriais da Universidade de São Paulo), juízo crítico (Escala de Avaliação de Crenças de Brown), tiques (Escala de Gravidade Global de Tiques de Yale) e qualidade de vida (questionário genérico de avaliação de qualidade de vida, Medical Outcome Quality of Life Scale Short-form-36 e Escala de Avaliação Social). O treinamento dos avaliadores consistiu em assistir cinco entrevistas filmadas e entrevistar cinco pacientes junto com um pesquisador mais experiente, antes de entrevistar pacientes sozinhos. A confiabilidade entre todos os líderes de grupo para os instrumentos mais importantes (Structured Clinical Interview for DSM-IV, Dimensional Yale-Brown Obsessive-Compulsive Scale, Universidade de São Paulo Sensory Phenomena Scale ) foi medida após seis entrevistas completas. RESULTADOS: A confiabilidade entre avaliadores foi de 96%. Até março de 2008, 630 pacientes com transtorno obsessivo-compulsivo tinham sido sistematicamente avaliados. A média de idade (±SE) foi de 34,7 (±0,51), 56,3% eram do sexo feminino e 84,6% caucasianos. Os sintomas obsessivo-compulsivos mais prevalentes foram os de simetria e os de contaminação. As comorbidades psiquiátricas mais comuns foram depressão maior, ansiedade generalizada e transtorno de ansiedade social. O transtorno de controle de impulsos mais comum foi escoriação neurótica. CONCLUSÃO: Este consórcio de pesquisa, pioneiro no Brasil, permitiu delinear o perfil sociodemográfico, clínico e terapêutico do paciente com transtorno obsessivo-compulsivo em uma grande amostra clínica de pacientes. O Consórcio Brasileiro de Pesquisa em Transtornos do Espectro Obsessivo-Compulsivo estabeleceu uma importante rede de colaboração de investigação clínica padronizada sobre o transtorno obsessivo-compulsivo e pode abrir o caminho para projetos semelhantes destinados a integrar outros grupos de pesquisa no Brasil e em todo o mundo.

D-n-forced symmetry breaking of O(2)-equivariant problems

We use singularity theory to classify forced symmetry-breaking bifurcation problemsf(z, lambda, mu) = f(1)(z, lambda) + muf(2)(z, lambda, mu) = 0,where f(1) is O(2)-equivariant and f(2) is D-n-equivariant with the orthogonal group actions on z is an element of R-2. Forced symmetry breaking occurs when the symmetry of the equation changes when parameters are varied. We explicitly apply our results to the branching of subharmonic solutions in a model periodic perturbation of an autonomous equation and sketch further applications.

Cellular recruitment and cytokine generation in a rat model of allergic lung inflammation are differentially modulated by progesterone and estradiol

We evaluated the role of estradiol and progesterone in allergic lung inflammation. Rats were ovariectomized (Ovx) and, 7 days later, were sensitized with ovalbumin (OA) and challenged after 2 wk with inhaled OA; experiments were performed 1 day thereafter. Ovx-allergic rats showed reduced cell recruitment into the bronchoalveolar lavage (BAL) fluid relative to sham-Ovx allergic rats, as was observed in intact allergic rats treated with ICI-182,780. Estradiol increased the number of cells in the BAL of Ovx-allergic rats, whereas progesterone induced an additional reduction. Cells of BAL and bone marrow (BM) of Ovx-allergic rats released elevated amounts of IL-10 and reduced IL-1 beta and TNF-alpha. BM cells of Ovx-allergic rats released increased amounts of IL-10 and lower amounts of IL-4. Estradiol treatment of Ovx-allergic rats decreased the release of IL-10 but increased that of IL-4 by BM cells. Estradiol also caused an increased release of IL-1 beta and TNF-alpha by BAL cells. Progesterone significantly increased the release of IL-10, IL-1 beta, and TNF-alpha by BAL cells and augmented that of IL-4 by BM cells. Degranulation of bronchial mast cells from Ovx rats was reduced after in vitro challenge, an effect reverted by estradiol but not by progesterone. We suggest that the serum estradiol-to-progesterone ratio might drive cellular recruitment, modulating the pulmonary allergy and profile of release of anti-inflammatory or inflammatory cytokines. The existence of such dual hormonal effects suggests that the hormone therapy of asthmatic postmenopausal women and of those suffering of premenstrual asthma should take into account the possibility of worsening the pulmonary conditions.

Pulmonary neutrophil recruitment and bronchial reactivity in formaldehyde-exposed rats are modulated by mast cells and differentially by neuropeptides and nitric oxide

We have used a pharmacological approach to study the mechanisms underlying the rat lung injury and the airway reactivity changes induced by inhalation of formaldehyde (FA) (1% formalin solution, 90 min once a day, 4 days). The reactivity of isolated tracheae and intrapulmonary bronchi were assessed in dose-response curves to methacholine (MCh). Local and systemic inflammatory phenomena were evaluated in terms of leukocyte countings in bronchoalveolar lavage (BAL) fluid, blood, bone marrow lavage and spleen. Whereas the tracheal reactivity to MCh did not change, a significant bronchial hyporesponsiveness (BHR) was found after FA inhalation as compared with naive rats. Also, FA exposure significantly increased the total cell numbers in BAL, in peripheral blood and in the spleen, but did not modify the counts in bone marrow. Capsaicin hindered the increase of leukocyte number recovered in BAL fluid after FA exposure. Both compound 48/80 and indomethacin were able to prevent the lung neutrophil influx after FA, but indomethacin had no effect on that of mononuclear cells. Following FA inhalation, the treatment with sodium cromoglycate (SCG), but not with the nitric oxide (NO) synthase inhibitor L-NAME, significantly reduced the total cell number in BAL. Compound 48/80, L-NAME and SCG significantly prevented BHR to MCh after FA inhalation, whereas capsaicin was inactive in this regard. on the other hand, indomethacin exacerbated BHR. These data suggest that after FA inhalation, the resulting lung leukocyte influx and BHR may involve nitric oxide, airway sensory fibers and mast cell-derived mediators. The effect of NO seemed to be largely restricted to the bronchial tonus, whereas neuropeptides appeared to be linked to the inflammatory response, therefore indicating that the mechanisms responsible for the changes of airway responsiveness caused by FA may be separate from those underlying its inflammatory lung effects. (c) 2005 Elsevier B.V. All rights reserved.