ABSTRACT
An adult male greater bulldog bat (Noctilio leporinus) was found dead in a suburban area in the municipality of Patos, Paraiba, northeastern Brazil. At post-mortem examination, the bat was emaciated and had multifocal to coalescent grey, crusted, dry, scaly cutaneous lesions, irregularly distributed over the dorsal thoracoabdominal region, muzzle, labial commissures, ears and dorsoventral surfaces of the patagia. Histopathology revealed numerous longitudinal and transverse sections of fungal organisms, with weakly basophilic walls, associated with multifocal areas of ulceration of the epidermis, necrosis, rupture and discontinuity of collagen fibres in the dermis without any inflammatory response. Molecular identification matched the organism to Cladosporium spp, Curvularia spp, Exserohilum spp, Bipolaris spp (100%) and Alternaria spp (97%), all of which have been associated with phaeohyphomycosis. Phaeohyphomycosis should be included as a differential diagnosis of cutaneous lesions in chiropterans.
Subject(s)
Chiroptera , Phaeohyphomycosis , Male , Animals , Brazil , Phaeohyphomycosis/veterinary , Skin , CladosporiumABSTRACT
The inclusion of corn-dried distillers' grains (DDG) could be an alternative supplement to increase animal performance, nitrogen efficiency usage (NEU), and decrease enteric methane (CH4) emissions. Our goal was to determine whether DDG could replace a traditional supplement (cottonseed meal) without affecting animal performance, N balance, and CH4 emissions. The experiment was conducted during the forage growing season (December to April), with 15 d adaptation, and a 112 d experimental period. The experimental design was completely randomized with four treatments: a mineral supplement (MS), cottonseed meal supplement (CS), 50% replacement of CS by DDG (50DDG), and 100% replacement of CS by DDG (100DDG). Cottonseed meal and DDG were used as protein supplement. A total of 12 paddocks, 3 per treatment, were used to measure forage mass: morphological and chemical composition of forage, forage allowance, and animal performance. Six animals per treatment were used to evaluate DM intake, digestibility, CH4 emissions, microbial protein production (MCP), and NEU of each treatment. Eighty-one Young Nellore bulls (48 testers, 12 per treatments and 33 adjusters) with initial BW of 255⯱â¯5â¯kg (10-12â¯months old) were supplemented with each supplement type at a level of 0.3% of BW. Pasture management was continuous stocking with a variable stocking rate (put-and-take). Enteric CH4 was measured using the gas tracer technique. The MCP was quantified using purine derivatives and the NEU mass balance. No differences were found in nutrient intake (Pâ¯>â¯0.228). Individual animal performance and gain per area were higher in the treatments with concentrates compared with that of MS; however, there was no difference among treatments CS, 50DDG, and 100DDG. The ADG was 0.83 for MS and 1.08â¯kg/animal/d when supplemented (Pâ¯<â¯0.05). Gain per hectare was 709â¯kg/ha for MS and 915â¯kg/ha when supplemented with concentrates (Pâ¯<â¯0.05). There was no difference in CH4 production among treatments that average 180â¯g/animal/d; however, CH4 per kg of gain was reduced with CS. The CH4 conversion factor averaged 5.91%. There was no difference in the synthesis of MCP and NEU. Corn DDG can replace 100% of cottonseed meal as a protein source for supplementation of young Nellore bulls grazing in tropical pastures without affecting animal performance, NEU, MCP, and CH4 emissions.
Subject(s)
Animal Feed , Zea mays , Animal Feed/analysis , Animals , Cattle , Diet/veterinary , Dietary Supplements , Digestion , Male , NitrogenABSTRACT
A captive 7-year-old male bush dog (Speothos venaticus) was diagnosed with lymphoma affecting the kidneys, adrenal glands, liver, and spleen. The animal developed renal failure and was euthanized due to poor prognosis. Grossly, both kidneys were enlarged with multiple nodules. Histologically, the neoplasm was an infiltrative and poorly demarcated round cell tumor. Two morphologically distinct cell populations were observed, smaller cells with a lymphocytic morphology, and another population of larger and pleomorphic cells. Most of the smaller cell population, approximately 40% of the population within the neoplasm, were CD3 positive. Neoplastic cells were CD45, CD11d, and granzime B positive, and negative for CD20, CD79a, PAX5, CD163, and myeloperoxidase. This is the first reported case of lymphoma in a bush dog. This report demonstrated the suitability of several cell surface markers for differential diagnosis of round cell tumors in this species.(AU)
Um cachorro-do-mato-vinagre (Speothos venaticus), de sete anos de idade, mantido em cativeiro, foi diagnosticado com linfoma que havia afetado os rins, as adrenais, o fígado e o baço. O animal desenvolveu insuficiência renal e foi submetido à eutanásia devido ao prognóstico desfavorável. Macroscopicamente, ambos os rins estavam aumentados de tamanho, com múltiplos nódulos. Histologicamente, a neoplasia era infiltrativa, pobremente delimitada e constituída por células redondas. Duas populações distintas foram observadas: células pequenas com morfologia linfocítica e células grandes e pleomórficas. A maior parte da população de células pequenas, correspondendo a aproximadamente 40% da população celular na neoplasia, foi positiva para CD3. As células neoplásicas foram positivas para CD45, CD11d e granzima B e negativas para CD20, CD79a, PAX5, CD163 e mieloperoxidase. Este é o primeiro caso de linfoma em um cachorro-do-mato-vinagre. Tal relado demonstra a utilidade de vários marcadores de superfície celular para o diagnóstico diferencial de tumores de células redondas nessa espécie.(AU)
Subject(s)
Animals , Male , Dogs , Extranodal Extension , Lymphoma/veterinary , Immunohistochemistry/veterinary , Renal Insufficiency/veterinary , Animals, WildABSTRACT
A captive 7-year-old male bush dog (Speothos venaticus) was diagnosed with lymphoma affecting the kidneys, adrenal glands, liver, and spleen. The animal developed renal failure and was euthanized due to poor prognosis. Grossly, both kidneys were enlarged with multiple nodules. Histologically, the neoplasm was an infiltrative and poorly demarcated round cell tumor. Two morphologically distinct cell populations were observed, smaller cells with a lymphocytic morphology, and another population of larger and pleomorphic cells. Most of the smaller cell population, approximately 40% of the population within the neoplasm, were CD3 positive. Neoplastic cells were CD45, CD11d, and granzime B positive, and negative for CD20, CD79a, PAX5, CD163, and myeloperoxidase. This is the first reported case of lymphoma in a bush dog. This report demonstrated the suitability of several cell surface markers for differential diagnosis of round cell tumors in this species.(AU)
Um cachorro-do-mato-vinagre (Speothos venaticus), de sete anos de idade, mantido em cativeiro, foi diagnosticado com linfoma que havia afetado os rins, as adrenais, o fígado e o baço. O animal desenvolveu insuficiência renal e foi submetido à eutanásia devido ao prognóstico desfavorável. Macroscopicamente, ambos os rins estavam aumentados de tamanho, com múltiplos nódulos. Histologicamente, a neoplasia era infiltrativa, pobremente delimitada e constituída por células redondas. Duas populações distintas foram observadas: células pequenas com morfologia linfocítica e células grandes e pleomórficas. A maior parte da população de células pequenas, correspondendo a aproximadamente 40% da população celular na neoplasia, foi positiva para CD3. As células neoplásicas foram positivas para CD45, CD11d e granzima B e negativas para CD20, CD79a, PAX5, CD163 e mieloperoxidase. Este é o primeiro caso de linfoma em um cachorro-do-mato-vinagre. Tal relado demonstra a utilidade de vários marcadores de superfície celular para o diagnóstico diferencial de tumores de células redondas nessa espécie.(AU)
Subject(s)
Animals , Male , Dogs , Extranodal Extension , Lymphoma/veterinary , Immunohistochemistry/veterinary , Renal Insufficiency/veterinary , Animals, WildABSTRACT
The aim of this work was to evaluate the effectiveness of different enzymatic complexes in productive and qualitative traits of broilers. A total of 936 male Hubbard chicks were allocated in a randomized block design with six treatments, six replicates, and 26 birds per plot. The treatments consisted of a positive control, a negative control and the addition of four enzymatic complexes to the rations, with energy devaluation according to the energy matrix of the enzymes. Performance and carcass and meat quality traits were analyzed. The use of the different enzymatic complexes (CE1 and CE2) and their devaluations provided higher feed and energy intake compared to treatments CP, CN, CE3 and CE4, but did not affect weight gain, feed conversion ratio or productive efficiency index, nor did it influence carcass, cut or meat quality traits. It is concluded that the use of enzymatic complexes changes the performance of birds without altering carcass and meat traits.(AU)
O objetivo desse trabalho foi avaliar a efetividade de diferentes complexos enzimáticos nas características produtivas e qualitativas em frangos de corte. Foram utilizados 936 pintainhos de corte macho, da linhagem Hubbard, distribuídos em um delineamento em blocos ao acaso, com seis tratamentos, seis repetições e 26 aves por parcela. Os tratamentos consistiram em controle positivo, controle negativo e utilização de quatro complexos enzimáticos utilizados em rações com desvalorização energética de acordo com a matriz energética das enzimas. Foi analisado o desempenho, características de carcaça e qualidade de carne. O uso dos diferentes complexos enzimáticos (CE1 e CE2) e suas desvalorizações proporcionaram maior consumo de ração e de energia em relação aos tratamentos CP, CN, CE3 e CE4, porém isto não refletiu no ganho de peso, conversão alimentar, índice de eficiência produtiva, além das características de carcaça, cortes e qualidade de carne. Conclui-se que a utilização de componentes enzimáticos altera desempenho das aves, sem alterar as características de carcaça e carne.(AU)
Subject(s)
Animals , Male , Infant, Newborn , Chickens/growth & development , Chickens/physiology , Enzymes/adverse effects , Animal Feed , Food AdditivesABSTRACT
The aim of this work was to evaluate the effectiveness of different enzymatic complexes in productive and qualitative traits of broilers. A total of 936 male Hubbard chicks were allocated in a randomized block design with six treatments, six replicates, and 26 birds per plot. The treatments consisted of a positive control, a negative control and the addition of four enzymatic complexes to the rations, with energy devaluation according to the energy matrix of the enzymes. Performance and carcass and meat quality traits were analyzed. The use of the different enzymatic complexes (CE1 and CE2) and their devaluations provided higher feed and energy intake compared to treatments CP, CN, CE3 and CE4, but did not affect weight gain, feed conversion ratio or productive efficiency index, nor did it influence carcass, cut or meat quality traits. It is concluded that the use of enzymatic complexes changes the performance of birds without altering carcass and meat traits.
O objetivo desse trabalho foi avaliar a efetividade de diferentes complexos enzimáticos nas características produtivas e qualitativas em frangos de corte. Foram utilizados 936 pintainhos de corte macho, da linhagem Hubbard, distribuídos em um delineamento em blocos ao acaso, com seis tratamentos, seis repetições e 26 aves por parcela. Os tratamentos consistiram em controle positivo, controle negativo e utilização de quatro complexos enzimáticos utilizados em rações com desvalorização energética de acordo com a matriz energética das enzimas. Foi analisado o desempenho, características de carcaça e qualidade de carne. O uso dos diferentes complexos enzimáticos (CE1 e CE2) e suas desvalorizações proporcionaram maior consumo de ração e de energia em relação aos tratamentos CP, CN, CE3 e CE4, porém isto não refletiu no ganho de peso, conversão alimentar, índice de eficiência produtiva, além das características de carcaça, cortes e qualidade de carne. Conclui-se que a utilização de componentes enzimáticos altera desempenho das aves, sem alterar as características de carcaça e carne.
Subject(s)
Male , Animals , Infant, Newborn , Enzymes/adverse effects , Chickens/growth & development , Chickens/physiology , Animal Feed , Food AdditivesABSTRACT
INTRODUCTION: A bladder diary (BD) is a simple and non-invasive method of evaluating people with lower urinary tract symptoms (LUTS). Recently, the ICCS recommended a 48-h daytime frequency and volume chart (which does not need to be recorded on 2 consecutive days) to evaluate lower urinary tract (LUT) dysfunction. However, some studies on adults have demonstrated that a minimum of 3 days is required. It is believed that, to date, there are no studies in the literature that compare a 2-day BD with a 3-day BD. The advantages of a BD over a shorter period of time are the simplicity and possible better parent compliance. OBJECTIVE: The aim of this study was to evaluate if a 2-day BD is statistically and clinically comparable to a 3-day BD. STUDY DESIGN: A voiding diary was filled in over a 3-day period for 92 children (ages ranged from to 3-16 years, mean 7.9 ± 3.07) attending the present institution. By using the voiding diary, the following parameters were calculated: urination frequency, maximum and average volumes of urine (MVV and AVV) and fluid intake. The diary considered the 2 days as the first and second days of the 3-day diary. RESULTS: Out of the 92 children, eight (8.7%) did not properly complete the diary. The sample predominantly comprised females (n = 55, 59.8%). No differences were seen between 2-day and 3-day bladder diaries regarding fluid intake, maximum and average voided volume. The sensitivity, specificity, positive and negative predictive values of the 2-day bladder diary for detecting frequency were 83.4%, 91.7%, 80% and 93.2%, and for low bladder capacity they were 97.2%, 90.9%, 99% and 88%, respectively (Table). DISCUSSION: In a 2006 document, the ICCS recommended that a bladder diary be kept for 3 days, but in new documentation (2014) there is a reference stating that 2 days are enough. Bladder capacity is an important parameter in evaluating LUTS. Using a 2-day BD, the data showed that only a small percentage of reduced bladder capacity diagnosis would be lost. CONCLUSION: When using the 2-day diary, a 16% false negative rate for frequency should be expected. A 2-day bladder diary is sufficient to evaluate bladder capacity and fluid intake.
Subject(s)
Lower Urinary Tract Symptoms/diagnosis , Medical Records/statistics & numerical data , Adolescent , Child , Child, Preschool , Female , Humans , Male , Time FactorsABSTRACT
There is an increasing evidence that populations of ectotherms can diverge genetically in response to different climatic conditions, both within their native range and (in the case of invasive species) in their new range. Here, we test for such divergence in invasive whitefly Bemisia tabaci populations in tropical Colombia, by considering heritable variation within and between populations in survival and fecundity under temperature stress, and by comparing population differences with patterns established from putatively neutral microsatellite markers. We detected significant differences among populations linked to mean temperature (for survival) and temperature variation (for fecundity) in local environments. A QST - FST analysis indicated that phenotypic divergence was often larger than neutral expectations (QST > FST ). Particularly, for survival after a sublethal heat shock, this divergence remained linked to the local mean temperature after controlling for neutral divergence. These findings point to rapid adaptation in invasive whitefly likely to contribute to its success as a pest species. Ongoing evolutionary divergence also provides challenges in predicting the likely impact of Bemisia in invaded regions.
Subject(s)
Adaptation, Biological , Hemiptera/physiology , Tropical Climate , Animals , Colombia , Female , Fertility , Heat-Shock Response , Introduced Species , Male , Microsatellite Repeats , Molecular Sequence DataABSTRACT
BACKGROUND & AIMS: Malnutrition is related with pulmonary disease. The aim was to analyze the association of lung function respectively to nutritional status, identified pulmonary pathogens and socioeconomic condition of patients attending a pediatric CF reference center. METHODS: Cross-sectional study performed with CF patients aged 6 to 18 years attending a CF-Center in southern Brazil. Nutritional status, plasma albumin level and pulmonary bacterial colonization were assessed. The outcome studied was forced expiratory volume in 1 second (FEV1). RESULTS: Eighty-five patients were included in this study. FEV1 was significantly associated with body mass index (BMI) percentiles, plasma albumin level and methicillin resistant Staphylococcus aureus (MRSA) pulmonary colonization. Regression analysis showed that BMI below the 10th percentile was associated with a 25.58% drop in FEV1, and plasma albumin levels equal to or lower than 4.1 mg/dL was associated with 18.6% FEV1 reduction. FEV1 was 14.4% lower in the MRSA infected patients. Plasma albumin of 4.25 mg/dL predicted FEV1 of 60% with 76.9% sensitivity and 72.2% specificity, and 85.7% accuracy. The socioeconomic status was not association with pulmonary function. CONCLUSION: BMI below the 10th percentile and albumin below 4.1 mg/dL were predictors of low FEV1. Chronic MRSA infection was associated with lower FEV1. Longitudinal studies may better complement these results.
Subject(s)
Cystic Fibrosis/blood , Cystic Fibrosis/physiopathology , Lung/physiopathology , Nutritional Status , Respiratory Function Tests , Serum Albumin/analysis , Adolescent , Body Mass Index , Brazil , Child , Chronic Disease , Cross-Sectional Studies , Female , Forced Expiratory Volume , Humans , Lung Diseases/microbiology , Male , Malnutrition/complications , Malnutrition/physiopathology , Methicillin-Resistant Staphylococcus aureus/chemistry , Sample Size , Socioeconomic Factors , Staphylococcal Infections/blood , Staphylococcal Infections/physiopathologyABSTRACT
The effect of an aversive stimulus represented by contact with a hot plate on the heart rate of Megalobulimus mogianensis was evaluated with electrocardiogram recording in intact snails (N = 8). All stimulated animals showed an increase in heart rate, with mean values ranging from 35.6 +/- 1.2 (basal heart rate) to 43.8 +/- 0.9 bpm (post-stimulation heart rate). The cardioacceleration was followed by gradual recovery of the basal heart rate, with mean recovery times varying from 4.3 +/- 0.3 to 5.8 +/- 0.6 min. Repetition of the stimulus did not affect the magnitude of variation nor did it influence the basal heart rate recovery time. To investigate the role of the cardiac nerve in mediating the heart rate alterations induced by the aversive stimulus, denervated (N = 8) and sham-operated (N = 8) animals were also tested. Although the aversive stimulus caused the heart rate to increase significantly in both experimental groups, the mean increase in heart rate in denervated animals (4.4 +/- 0.4 bpm) was 57% of the value obtained in sham-operated animals (7.7 +/- 1.3 bpm), indicating that the cardiac nerve is responsible for 43% of the cardioacceleration induced by the aversive stimulus. The cardioacceleration observed in denervated snails may be due to an increase in venous return promoted by the intense muscular activity associated with the withdrawal response. Humoral factors may also be involved. A probable delaying inhibitory effect of the cardiac nerve on the recuperation of the basal heart rate is suggested.
Subject(s)
Heart Rate/physiology , Heart/innervation , Snails/physiology , Animals , Electrocardiography , Heart/physiology , Hot Temperature , Muscles/physiology , Physical Stimulation/methods , Reaction Time/physiology , Reflex/physiologyABSTRACT
The effect of an aversive stimulus represented by contact with a hot plate on the heart rate of Megalobulimus mogianensis was evaluated with electrocardiogram recording in intact snails (N = 8). All stimulated animals showed an increase in heart rate, with mean values ranging from 35.6 ± 1.2 (basal heart rate) to 43.8 ± 0.9 bpm (post-stimulation heart rate). The cardioacceleration was followed by gradual recovery of the basal heart rate, with mean recovery times varying from 4.3 ± 0.3 to 5.8 ± 0.6 min. Repetition of the stimulus did not affect the magnitude of variation nor did it influence the basal heart rate recovery time. To investigate the role of the cardiac nerve in mediating the heart rate alterations induced by the aversive stimulus, denervated (N = 8) and sham-operated (N = 8) animals were also tested. Although the aversive stimulus caused the heart rate to increase significantly in both experimental groups, the mean increase in heart rate in denervated animals (4.4 ± 0.4 bpm) was 57 percent of the value obtained in sham-operated animals (7.7 ± 1.3 bpm), indicating that the cardiac nerve is responsible for 43 percent of the cardioacceleration induced by the aversive stimulus. The cardioacceleration observed in denervated snails may be due to an increase in venous return promoted by the intense muscular activity associated with the withdrawal response. Humoral factors may also be involved. A probable delaying inhibitory effect of the cardiac nerve on the recuperation of the basal heart rate is suggested.
Subject(s)
Animals , Heart Rate/physiology , Heart/innervation , Snails/physiology , Electrocardiography , Hot Temperature , Heart/physiology , Muscles/physiology , Physical Stimulation/methods , Reaction Time/physiology , Reflex/physiologyABSTRACT
Lungfish represent a probable sister group to the land vertebrates. Lungfish and tetrapods share features of respiratory control, including central, peripheral and intrapulmonary CO(2) receptors. We investigated whether or not central chemoreceptors in the lungfish, L. paradoxa, are stimulated by CO(2) and/or pH. Ventilation was measured by pneumotachography for diving animals. The fourth cerebral ventricle was equipped with two catheters for superfusion. Initially, two control groups were compared: (1) catheterized animals with no superfusion and (2) animals superfused with mock CSF solutions at pH = 7.45; PCO(2) = 21 mmHg. The two groups had virtually the same ventilation of about 40 ml BTPS kg(-1) h(-1) (P > 0.05). Next, PCO(2) was increased from 21 to 42 mmHg, while pH(CSF) was kept at 7.45, which increased ventilation from 40 to 75 ml BTPS kg(-1) h(-1). Conversely, a decrease of pH(CSF) from 7.45 to 7.20 (PCO(2) = 21 mmHg) increased ventilation to 111 ml BTPS kg(-1) h(-1). Further decreases of pH(CSF) had little effect on ventilation, and the combination of pH(CSF) = 7.10 and PCO(2) = 42 mmHg reduced ventilation to 63 ml BTPS kg(-1) h(-1).
Subject(s)
Carbon Dioxide/pharmacology , Central Nervous System/physiology , Chemoreceptor Cells/drug effects , Chemoreceptor Cells/physiology , Fishes/physiology , Respiration , Respiratory Physiological Phenomena , Animals , Carbon Dioxide/administration & dosage , Cerebrospinal Fluid/chemistry , Hydrogen-Ion Concentration , Partial Pressure , Respiration/drug effects , Respiratory Mechanics , Tidal VolumeABSTRACT
Lungfish are closely related to terrestrial vertebrates (tetrapoda). Like tetrapods, the South American lungfish (Lepidosiren paradoxa) has central chemoreceptors involved in regulation of acid-base status. However, no data were available on peripheral CO(2)/[H(+)] receptors. Therefore, we tested the hypothesis that such receptors exist by measuring the ventilatory responses during a 5h exposure to combined aquatic/gas phase hypercarbia 7% (approximately 49 mmHg). Normocarbic control ventilation was 22 ml BTPS kg(-1)h(-1), and hypercarbia increased ventilation to 175 ml BTPS kg(-1)h(-1) at 5h. This procedure was repeated with the modification that normocarbic mock CSF (pH 7.45; P(CO2) = 20.7 mmHg) was applied to superfuse the cerebral ventricular system during the last 2h of the experiment. This served to eliminate the hypercarbic stimulus to the central chemoreceptors, while possible responses from peripheral chemoreceptors would remain intact. Peripheral receptors were detected, since ventilation became reduced to 62 ml BTPS kg(-1)h(-1) (P<0.05), which exceeds the initial normocarbic control ventilation (P<0.05). Based on this, the peripheral contribution accounted for 20% of the total response to hypercarbia, similar to the contribution of these receptors in man.
Subject(s)
Acid-Base Equilibrium/physiology , Chemoreceptor Cells/physiology , Fishes/physiology , Respiratory Mechanics/physiology , Algorithms , Animals , Catheterization , Cerebrospinal Fluid/physiology , Drive , Lung/physiology , Tidal Volume/physiologyABSTRACT
Findings by our group have shown that the dorsolateral telencephalon of Gymnotus carapo sends efferents to the mesencephalic torus semicircularis dorsalis (TSd) and that presumably this connection is involved in the changes in electric organ discharge (EOD) and in skeletomotor responses observed following microinjections of GABA A antagonist bicuculline into this telencephalic region. Other studies have implicated the TSd or its mammalian homologue, the inferior colliculus, in defensive responses. In the present study, we explore the possible involvement of the TSd and of the GABA-ergic system in the modulation of the electric and skeletomotor displays. For this purpose, different doses of bicuculline (0.98, 0.49, 0.245, and 0.015 mM) and muscimol (15.35 mM) were microinjected (0.1 microL) in the TSd of the awake G. carapo. Microinjection of bicuculline induced dose-dependent interruptions of EOD and increased skeletomotor activity resembling defense displays. The effects of the two highest doses showed maximum values at 5 min (4.3 +/- 2.7 and 3.8 +/- 2.0 Hz, P < 0.05) and persisted until 10 min (11 +/- 5.7 and 8.7 +/- 5.2 Hz, P < 0.05). Microinjections of muscimol were ineffective. During the interruptions of EOD, the novelty response (increased frequency in response to sensory novelties) induced by an electric stimulus delivered by a pair of electrodes placed in the water of the experimental cuvette was reduced or abolished. These data suggest that the GABA-ergic mechanisms of the TSd inhibit the neural substrate of the defense reaction at this midbrain level.
Subject(s)
Behavior, Animal/drug effects , Bicuculline/pharmacology , Gymnotiformes/physiology , Mesencephalon/drug effects , Muscimol/pharmacology , Animals , Behavior, Animal/physiology , Bicuculline/administration & dosage , Defense Mechanisms , Drug Interactions/physiology , Electric Organ/drug effects , Electric Organ/physiology , Electric Stimulation , GABA Agonists/pharmacology , GABA Antagonists/pharmacology , Mesencephalon/physiology , Microinjections , Movement/drug effects , Movement/physiology , Muscimol/administration & dosage , Neural Pathways/drug effects , Neural Pathways/physiologyABSTRACT
Findings by our group have shown that the dorsolateral telencephalon of Gymnotus carapo sends efferents to the mesencephalic torus semicircularis dorsalis (TSd) and that presumably this connection is involved in the changes in electric organ discharge (EOD) and in skeletomotor responses observed following microinjections of GABA A antagonist bicuculline into this telencephalic region. Other studies have implicated the TSd or its mammalian homologue, the inferior colliculus, in defensive responses. In the present study, we explore the possible involvement of the TSd and of the GABA-ergic system in the modulation of the electric and skeletomotor displays. For this purpose, different doses of bicuculline (0.98, 0.49, 0.245, and 0.015 mM) and muscimol (15.35 mM) were microinjected (0.1 æL) in the TSd of the awake G. carapo. Microinjection of bicuculline induced dose-dependent interruptions of EOD and increased skeletomotor activity resembling defense displays. The effects of the two highest doses showed maximum values at 5 min (4.3 ± 2.7 and 3.8 ± 2.0 Hz, P < 0.05) and persisted until 10 min (11 ± 5.7 and 8.7 ± 5.2 Hz, P < 0.05). Microinjections of muscimol were ineffective. During the interruptions of EOD, the novelty response (increased frequency in response to sensory novelties) induced by an electric stimulus delivered by a pair of electrodes placed in the water of the experimental cuvette was reduced or abolished. These data suggest that the GABA-ergic mechanisms of the TSd inhibit the neural substrate of the defense reaction at this midbrain level.
Subject(s)
Animals , Behavior, Animal/physiology , Bicuculline/pharmacology , Gymnotiformes/physiology , Mesencephalon/physiology , Muscimol/pharmacology , Behavior, Animal/drug effects , Bicuculline/administration & dosage , Defense Mechanisms , Drug Interactions/physiology , Electric Stimulation , Electric Organ/drug effects , Electric Organ/physiology , GABA Agonists/pharmacology , GABA Antagonists/pharmacology , Microinjections , Mesencephalon/drug effects , Movement/drug effects , Movement/physiology , Muscimol/administration & dosage , Neural Pathways/drug effects , Neural Pathways/physiologyABSTRACT
The effects of a brief jet of water delivered to the anterior portion of body-head on the heart rate of Megalobulimus mogianensis were determined in a group of intact snails (N = 8), previously prepared for electrocardiogram recording. The heart rate was significantly increased following stimulation. Nevertheless, with repetition of the stimulus there was a significant decrease in the magnitude of the heart rate variation and in the time for the basal heart rate to recover (first stimulus, 7.4 +/- 1.2 bpm and 15.5 +/- 1.8 min; second stimulus, 4.8 +/- 1.0 bpm and 10.6 +/- 1.5 min; third stimulus, 5.0 +/- 0.3 bpm and 11.1 +/- 1.8 min), indicating that this behavioral response undergoes early habituation. To determine the role of the cardiac nerve in mediating the heart rate alterations induced by the jet of water two other groups were tested: denervated animals (N = 8) and sham-operated control animals (N = 8). Although the innocuous stimulus caused the heart rate to increase significantly in both experimental groups, the mean increase in heart rate in denervated animals (3.2 +/- 0.4 bpm) was 41% of the value obtained in sham-operated animals (7.8 +/- 1.5 bpm), indicating that the cardiac nerve is responsible for 59% of the cardioacceleration induced by the innocuous stimulus. The increase in heart rate observed in denervated animals may be due to an increase in venous return promoted by the intense muscular activity associated with the retraction-protraction of the anterior part of the body induced by the jet of water.
Subject(s)
Heart Rate/physiology , Heart/innervation , Snails/physiology , Animals , Electrocardiography , Physical Stimulation/methodsABSTRACT
The effects of a brief jet of water delivered to the anterior portion of body-head on the heart rate of Megalobulimus mogianensis were determined in a group of intact snails (N = 8), previously prepared for electrocardiogram recording. The heart rate was significantly increased following stimulation. Nevertheless, with repetition of the stimulus there was a significant decrease in the magnitude of the heart rate variation and in the time for the basal heart rate to recover (first stimulus, 7.4 ± 1.2 bpm and 15.5 ± 1.8 min; second stimulus, 4.8 ± 1.0 bpm and 10.6 ± 1.5 min; third stimulus, 5.0 ± 0.3 bpm and 11.1 ± 1.8 min), indicating that this behavioral response undergoes early habituation. To determine the role of the cardiac nerve in mediating the heart rate alterations induced by the jet of water two other groups were tested: denervated animals (N = 8) and sham-operated control animals (N = 8). Although the innocuous stimulus caused the heart rate to increase significantly in both experimental groups, the mean increase in heart rate in denervated animals (3.2 ± 0.4 bpm) was 41 percent of the value obtained in sham-operated animals (7.8 ± 1.5 bpm), indicating that the cardiac nerve is responsible for 59 percent of the cardioacceleration induced by the innocuous stimulus. The increase in heart rate observed in denervated animals may be due to an increase in venous return promoted by the intense muscular activity associated with the retraction-protraction of the anterior part of the body induced by the jet of water.
Subject(s)
Animals , Heart Rate/physiology , Heart/innervation , Snails/physiology , Electrocardiography , Physical Stimulation/methodsABSTRACT
In the present study, the functional neuroanatomy of nigrotectal-tectonigral pathways as well as the effects of central administration of opioid antagonists on aversive stimuli-induced responses elicited by electrical stimulation of the midbrain tectum were determined. Central microinjections of naloxonazine, a selective mu(1)-opiod receptor antagonist, in the mesencephalic tectum (MT) caused a significant increase in the escape thresholds elicited by local electrical stimulation. Furthermore, either naltrexone or naloxonazine microinjected in the substantia nigra, pars reticulata (SNpr), caused a significant increase in the defensive thresholds elicited by electrical stimulation of the continuum comprised by dorsolateral aspects of the periaqueductal gray matter (dlPAG) and deep layers of the superior colliculus (dlSC), as compared with controls. These findings suggest an opioid modulation of GABAergic inhibitory inputs controlling the defensive behavior elicited by MT stimulation, in cranial aspects. In fact, iontophoretic microinjections of the neurotracer biodextran into the SNpr, a mesencephalic structure rich in GABA-containing neurons, show outputs to neural substrate of the dlSC/dlPAG involved with the generation and organization of fear- and panic-like reactions. Neurochemical lesion of the nigrotectal pathways increased the sensitivity of the MT to electrical (at alertness, freezing and escape thresholds) and chemical (blockade of GABA(A) receptors) stimulation, suggesting a tonic modulatory effect of the nigrotectal GABAergic outputs on the neural networks of the MT involved with the organization of the defensive behavior and panic-like reactions. Labeled neurons of the midbrain tectum send inputs with varicosities to ipsi and contralateral dlSC/dlPAG and ipsilateral substantia nigra, pars reticulata and compacta, in which the anterograde and retrograde tracing from a single injection indicates that the substantia nigra has reciprocal connections with the dlSC/dlPAG featuring close axo-somatic and axo-dendritic appositions in both locations. In addition, ultrastructural approaches show inhibitory axo-axonic synapses in MT and inhibitory axo-somatic/axo-axonic synapses in the SNpr. These findings, in addition to the psychopharmacological evidence for the interaction between opioid and GABAergic mechanisms in the cranial aspects of the MT as well as in the mesencephalic tegmentum, offer a neuroanatomical basis of a pre-synaptic opioid inhibition of GABAergic nigrotectal neurons modulating fear in defensive behavior-related structures of the cranial mesencephalon, in a short link, and through a major neural circuit, also in GABA-containing perikarya and axons of nigrotectal neurons.
Subject(s)
Mesencephalon/cytology , Mesencephalon/metabolism , Panic/physiology , Receptors, GABA-A/metabolism , Receptors, Opioid, mu/metabolism , Animals , Bicuculline/analogs & derivatives , Bicuculline/pharmacology , Electric Stimulation , GABA Antagonists/pharmacology , Male , Mesencephalon/drug effects , Microscopy, Electron , Naloxone/analogs & derivatives , Naloxone/pharmacology , Narcotic Antagonists/pharmacology , Neural Pathways , Neurons/metabolism , Neurons/ultrastructure , Periaqueductal Gray/cytology , Periaqueductal Gray/drug effects , Periaqueductal Gray/metabolism , Rats , Rats, Wistar , Receptors, Opioid, mu/antagonists & inhibitors , Substantia Nigra/cytology , Substantia Nigra/drug effects , Substantia Nigra/metabolism , Tectum Mesencephali/cytology , Tectum Mesencephali/drug effects , Tectum Mesencephali/metabolismABSTRACT
Nitric oxide (NO) promotes adenosine release in the striatum and hippocampus. Behavioral effects of the nitric oxide donor sodium nitroprusside were studied in mice and included an examination of spontaneous locomotion and catalepsy, which are behaviors modulated by adenosine. Sodium nitroprusside caused a dose-dependent (2, 4 and 6 mg/kg) decrease in locomotor activity and catalepsy at the dose of 6 mg/kg. These effects were substantially attenuated by pretreatment with the non-selective adenosine receptors antagonist theophylline (10 and 30 mg/kg). Moreover, combined treatment with theophylline (30 mg/kg) and sodium nitroprusside (6 mg/kg) induced limbic seizures in 23% of animals. The pretreatment with the selective adenosine A(1) receptor antagonist 8-cyclopentyl-1, 3-dimethylxanthine (CPT) (1.2 mg/kg) caused no effect on the spontaneous or sodium nitroprusside-induced behavior. These data suggest that these behavioral effects of sodium nitroprusside are at least partially mediated by adenosine in the striatum and hippocampus, probably via adenosine A(2A) receptors.
Subject(s)
Catalepsy/chemically induced , Motor Activity/drug effects , Nitric Oxide Donors/pharmacology , Theophylline/analogs & derivatives , Animals , Behavior, Animal/drug effects , Catalepsy/prevention & control , Dose-Response Relationship, Drug , Male , Mice , Nitroprusside/pharmacology , Purinergic P1 Receptor Antagonists , Theophylline/pharmacology , Time Factors , Vasodilator Agents/pharmacologyABSTRACT
The respiratory control in land vertebrates (Tetrapoda) is mainly linked to regulation of acid-base status, which involves peripheral and central chemoreceptors. The lungfish (Dipnoi) might constitute the sister group of all land vertebrates (Tetrapoda) and possess a combination of real lungs and reduced gills. In this context, we evaluated the possible presence of central respiratory chemoreceptors in the South American Lungfish, Lepidosiren paradoxa. Pulmonary ventilation and respiratory frequency increased significantly with reductions of CSF pH by means of mock CSF solutions. This suggests that Lepidosiren possess central acid-base receptors.