ABSTRACT L-carnitine perform a major role in transporting long-chain fatty acids into the mitochondria, where they are oxidized. It has been used in animal diets to decrease fat and increase muscle protein. The aim of this study was to evaluate the zootechnical performance, degree of steatosis in the liver, and genotoxic potential in Astyanax lacustris fed with different levels of L-carnitine (LC). Yellowtail tetra juveniles (n = 140) were distributed in 20 tanks of 70 L, with seven fish in each, in a water recirculation system with controlled temperature (27±0.1⁰C). The treatments with different levels of L-carnitine supplementation were: 0 (control), 250, 500, 750, and 1000 mg of LC per kg of food. The diets were provided twice a day for 60 days. The results showed that the different levels of LC did not affect (P>0.05) weight gain, survival, viscerosomatic index, and the liver hepatocytes showed a normal appearance. However, the use of LC supplementation showed genotoxic potential with a significant difference (P<0.05) for cell alterations when compared to the control at concentrations above 500mg kg-1.

RESUMO A L-carnitina exerce um papel importante no transporte de ácidos graxos de cadeia longa até a mitocôndria para serem oxidados e tem sido incorporada em rações para animais com o objetivo de diminuir a deposição de gordura e aumentar a proteína muscular. O objetivo deste trabalho foi avaliar o desempenho zootécnico, o grau de esteatose no fígado e o potencial genotóxico em Astyanax lacustris alimentados com diferentes níveis de L-carnitina (LC). Juvenis de lambari-do-rabo-amarelo (n=140) foram distribuídos em 20 caixas de 70L, sete peixes em cada, em um sistema de recirculação de água com temperatura controlada (27±0,1⁰C). Os tratamentos com os níveis de suplementação foram: 0 (controle), 250, 500, 750 e 1000 mg de LC kg-1 de ração. As dietas foram fornecidas duas vezes ao dia, durante 60 dias. Os resultados mostraram que os diferentes níveis de LC não influenciaram (P>0,05) o ganho de peso; a sobrevivência, o índice viscerossomático e os hepatócitos do fígado apresentaram-se com aparência normal. No entanto, a suplementação com LC apresentou potencial genotóxico com diferença significativa (P<0,05) para alterações celulares quando comparada ao controle em concentrações superiores a 500mg kg-1.

Abstract Recent years have seen a significant increase in the number of patents related to products and/or processes from aquatic organisms. Therefore, this paper aims to identify patent documents related to fishery resources available in the Brazilian patent system of the National Institute of Industrial Property. The research involved patents deposited/provided between 1999 and 2019, with the search in the system occurring through the descriptors: fish(s), mollusk(s), crustacean(s), and algae(s). A total of 363 records were found, where the group of fish presented the highest representation (40%), followed by algae (35%), crustaceans (14%), and mollusks (10%). The apex of 34 patent applications was found in the year 2011. Moreover, the results showed that the inventions registered are directed mainly to food, drugs, biocides, cosmetics, cultivation, processing and beneficiation, water treatment, patents for sustainable technologies (green patents), and biotechnology. Brazil holds most patent applications, followed by the United States of America (USA), which focuses its patent applications mainly on algae and fish. Considering the Brazilian biodiversity and the country’s technological development in recent years, Brazil needs to expand its technological autonomy and competitive capacity in the aquaculture and fisheries sector, mainly through the strengthening of R&D and innovation activities.

Abstract Hymenopteran parasitoids are important biological control agents in agroecosystems, and their diversity can be increased with habitat heterogeneity. Thus, the purpose of the study is to evaluate the influence of distance of rice-growing areas from natural fragment, type of crop management (organic and conventional) and crop stages (vegetative and reproductive stages) on parasitoids family diversity. The work took place in two irrigated rice crops, one with organic management (O.M.) and another one with conventional management (C.M.), in the municipality of Nova Santa Rita, RS, Brazil, during the 2013/2014 and 2014/2015 seasons. The parasitoids were collected with Malaise trap arranged at different distances in relation to the native vegetation surrounding the rice crop in both places. Specimens were collected twice a month from seeding until the rice harvest. Average abundance between management, distances and rice development were compared. The most abundant families were Platygastridae, Mymaridae, Encyrtidae, Eulophidae and Trichogrammatidae. Parasitoid average abundance was significantly higher on OM only in the second season. There was a negative correlation between distance from native vegetation and parasitoid abundance in C.M. areas. There were differences in the composition of the parasitoid assembly between the phenological stages of rice.

Resumo Os himenópteros parasitoides são importantes agentes de controle biológico em agroecossistemas com sua diversidade variando de acordo com a heterogeneidade de habitat. Nesse sentido, o objetivo deste trabalho foi avaliar a influência da distância de áreas com fragmentos de vegetação natural das áreas de cultivo de arroz, o tipo de manejo (orgânico ou convencional) e os estágios da cultura (vegetativo e reprodutivo) na diversidade de famílias de parasitoides. O trabalho foi conduzido em duas áreas com plantio de arroz irrigado, uma com manejo orgânico (MO) e outra com manejo convencional (CM), no município de Nova Santa Rita, RS, Brasil, durante a safra 2013/2014 e 2014/2015. Os parasitoides foram coletados com armadilha Malaise colocadas sob diferentes distâncias em relação a vegetação nativa circundante ao cultivo em ambas as áreas. Os espécimes foram coletados duas vezes ao mês da semeadura até a colheita. Foram comparadas a abundância média entre os manejos, distâncias e estágio de desenvolvimento do arroz. As famílias mais abundantes foram Platygastridae, Mymaridae, Encyrtidae, Eulophidae e Trichogrammatidae com suas abundâncias variando ao longo da safra. A abundância média de parasitoides foi significativamente maior no MO somente na segunda safra. Houve uma correlação negativa entre a distância da vegetação nativa e a abundância de parasitoides. Houve diferença na composição da assembleia de parasitoides entre os estágios fenológicos do arroz.

RESUMO: Herbicidas com efeito residual aplicados na cultura da soja podem afetar a produtividade de culturas de safrinha cultivadas em sucessão. Assim, objetivou-se nesta pesquisa avaliar o desempenho agronômico das culturas de feijão-azuki, crambe, milheto e pastagem de capim-xaraés cultivadas em sucessão à cultura da soja tratada com herbicidas residuais, bem como avaliar a contribuição no manejo de plantas daninhas. Quatro ensaios foram realizados em campo com a cultura da soja na safra, sendo em seguida sucedida pelos cultivos do feijão-azuki, crambe, milheto e pastagem de capim-xaraés como safrinha. Foi adotado o delineamento experimental em blocos ao acaso com quatro repetições e nove tratamentos, representados pela aplicação dos herbicidas residuais: imazethapyr (1,0 e 1,5 L ha-1), chlorimuron (60 e 90 g ha-1), fomesafen (1,0 e 1,5 L ha-1) e chloransulan-methyl (74,6 e 71,4 g ha-1) e a testemunha sem herbicida, mantida sob capina manual. Os herbicidas foram eficientes no controle de plantas daninhas na cultura da soja, não afetando a produtividade da cultura. Contudo, não houve contribuição da atividade residual dos herbicidas na redução da infestação nas culturas de safrinha. Os herbicidas não promoveram fitotoxicidade às culturas de crambe, feijão-azuki, milheto e pastagem de capim-xaraés, quando comparadas com a testemunha sem herbicida. O feijão-azuki tratado com chloransulan-methyl, independentemente da dose, apresentou maior rendimento de grãos. A ausência de fitotoxicidade nas culturas pode estar associada à precipitação pluviométrica incidente sobre a soja, que contribuiu na dissipação dos herbicidas.

ABSTRACT: Herbicides with residual effect applied in soybeans may affect the productivity of late harvest crops grown in succession. Thus, the objective of this research was to evaluate the agronomic performance of adzuki bean crops, crambe, millet and palisade grass pasture grown in succession to soybean crop treated with residual herbicides, as well as assess the contribution in weed management. Four trials were conducted in field conditions at the soybean crop in the harvest and then succeeded by adzuki bean crops, crambe, millet and palisade grass as late harvest. An experimental design was adopted in a randomized block arrangement with four replications and nine treatments represented by the application of residual herbicides: imazethapyr (1.0 and 1.5 L ha-1), chlorimuron (60 and 90 g ha-1), fomesafen (1.0 and 1.5 L ha-1) and chloransulan methyl (74.6 and 71.4 g ha-1) and without herbicide control, kept in manual weeding. The herbicides were efficient in weed control in soybeans, not affecting crop yield. However, there was no residual activity of herbicides contribution in reducing infestation in the late harvest crops. The herbicides did not promote phytotoxicity to crops of crambe, beans, millet and palisadegrass pasture when they were compared with the other treatments. The beans treated with methyl chloransulan, regardless of dose, showed a higher yield. The absence of phytotoxicity to crops can be associated with rainfall incident on soybens which contributed to the dissipation of herbicides.

RESUMO O rebanho de suínos brasileiro é constituído por diversas raças naturalizadas, entre elas a raça Piau, que é conhecida por sua rusticidade e pela grande deposição de toucinho. As raças naturalizadas, em comparação com as linhagens comerciais, podem ter uma maior resistência a doenças que circulam em seu território. Dessa forma, o presente estudo teve como objetivo verificar se existem diferenças no perfil sorológico contra o Porcine circovirus 2 (PVC2) entre suínos da raça Piau e de uma linhagem comercial de uma granja naturalmente infectada pelo PCV2. Foram realizadas mensurações da carga viral sérica por qPCR e dos níveis de anticorpos anti-PCV2 por meio da técnica de ELISA. Os resultados mostraram que a carga viral sérica se manteve homogênea em todos os animais e que os leitões da raça Piau apresentaram níveis de anticorpos superiores em comparação com os leitões da linhagem comercial (P=0,05), enquanto as porcas de linhagem comercial apresentaram níveis superiores aos da raça Piau (P<0,01). Este trabalho fornece indícios de que a raça Piau apresenta uma resposta imune humoral distinta diante de uma infecção natural pelo PCV2, quando comparada com a resposta desenvolvida pela linhagem comercial. Os resultados obtidos reforçam a importância da conservação das raças nativas.

ABSTRACT Brazilian pig population is made up of several naturalized breeds; among them the Piau breed is known for its rusticity and large fat stores. The naturalized breeds, in comparison with commercial ones, may have an increased resistance to diseases circulating in their territory. Thus, this study aimed to verify if there are differences between the serologic profile against Porcine circovirus 2 (PCV2) of Piau pigs and that of a commercial breed from a farm naturally infected by PCV2. The serum viral load was measured by qPCR, and levels of anti-PCV2 antibodies were measured by ELISA. The results showed that the serum viral load was similar across all animals. However, Piau piglets showed higher levels of antibodies compared to commercial piglets (P= 0.05), while sows of the commercial breed showed higher levels than the Piau breed (P< 0.01). There was not a statistical difference between pigs of different production stages in the seroprevalence of PCV2 or the blood viral load. This work demonstrates that, with regard to a natural PCV2 infection, the Piau breed has a different humoral immune response compared to the response developed by the commercial pigs. The results support the importance of conservation of native breeds.

Serotonergic mechanisms have an important function in the central control of circulation. Here, the acute effects of three selective serotonin (5-HT) reuptake inhibitors (SSRIs) on autonomic and cardiorespiratory variables were measured in rats. Although SSRIs require 2-3 weeks to achieve their full antidepressant effects, it has been shown that they cause an immediate inhibition of 5-HT reuptake. Seventy male Wistar rats were anesthetized with urethane and instrumented to record blood pressure, heart rate, renal sympathetic nerve activity (RSNA), and respiratory frequency. At lower doses, the acute cardiovascular effects of fluoxetine, paroxetine and sertraline administered intravenously were insignificant and variable. At middle and higher doses, a general pattern was observed, with significant reductions in sympathetic nerve activity. At 10 min, fluoxetine (3 and 10 mg/kg) reduced RSNA by -33±4.7 and -31±5.4%, respectively, without changes in blood pressure; 3 and 10 mg/kg paroxetine reduced RSNA by -35±5.4 and -31±5.5%, respectively, with an increase in blood pressure +26.3±2.5; 3 mg/kg sertraline reduced RSNA by -59.4±8.6%, without changes in blood pressure. Sympathoinhibition began 5 min after injection and lasted approximately 30 min. For fluoxetine and sertraline, but not paroxetine, there was a reduction in heart rate that was nearly parallel to the sympathoinhibition. The effect of these drugs on the other variables was insignificant. In conclusion, acute peripheral administration of SSRIs caused early autonomic cardiovascular effects, particularly sympathoinhibition, as measured by RSNA. Although a peripheral action cannot be ruled out, such effects are presumably mostly central.

A suplementação de L-arginina tem sido proposta para melhorar a função endotelial. Testou-se a hipótese de que a L-arginina melhora também a hipotensão pós-exercício (HPE) em hipertensos. Hipertensas fisicamente ativas foram distribuídas em grupo suplementado (SUP) (N = 10, 50 ± 1.8 anos) e placebo (PLA) (N = 10, 51.5 ± 1.6 anos). Elas realizaram duas sessões de caminhada em intensidade moderada com intervalo de 32 dias entre as sessões. Coletas sanguíneas e pressão arterial foram medidas pré e pós exercícios. No período entre as sessões, permaneceram fisicamente ativas e receberam 6gr diárias de L-arginina ou placebo. PLA não apresentou alteração na concentração sérica de nitrito/nitrato e PA em repouso ou em resposta ao exercício. SUP apresentou aumento na concentração basal de nitrito/nitrato plasmático (26.6 ± 2 para 44.6 ± 4µM , p < .05), que foi acompanhado por redução da PA basal (137/86.2 para 125.8/79mmHg, p < .05). O exercício realizado antes da suplementação não alterou a concentração sérica de nitrito/nitrato, mas a suplementação fez com que o exercício aumentasse estes níveis de 44.6 ± 4 para 51.8 ± 6µM (p < .05). Entretanto, não promoveu alterações na HPE. A suplementação de L-arginina melhora a produção de nitrito/nitrato e promove redução da PA de repouso, mas não altera a HPE em mulheres hipertensas de meia idade.

L-arginine supplementation has been proposed to improve endothelial. The hypothesis that L-arginine also improves post-exercise hypotension (PEH) in hypertensive individuals was tested in this study. Physically active hypertensive women were divided into supplemented (SUP) (n = 12, 50 ± 1.8 years) and placebo (PLA) (n = 14, 51.5 ± 1.6 years) groups performing two walking sessions at moderate intensity with interval of 32 days between sessions. Blood samples were collected and blood pressure (BP) was measured before and after exercise. In the period between sessions, they remained physically active and received daily 6g of L-arginine or placebo. PLA showed no change in serum nitrite/nitrate concentration and blood pressure at rest or in response to exercise. SUP showed increased basal nitrite/nitrate plasma concentration (26.6 ± 2 to 44.6 ± 4µM, p < .05), which was followed by reduction of basal BP (137/86.2 to 125.8/79mmHg, p < .05). The exercise performed before supplementation did not change the serum nitrite/nitrate concentration. After supplementation, the exercise promoted increases in levels from 44.6 ± 4 to 51.8 ± 6µ M (p < .05). However, it did not change the PEH. L-arginine supplementation improves the nitrite/nitrate production and decreases the resting BP, but does not change the PEH in hypertensive middle-aged women.

Este trabalho foi conduzido com o objetivo de avaliar a composição corporal e as exigências líquidas de proteína e energia para ganho de peso de novilhos Nelore e mestiços ½Limousin-Nelore terminados em pastagem de capim-mombaça. A pastagem de capim-mombaça (Panicum maximum) foi manejada em regime de lotação intermitente durante a época chuvosa, com oferta de forragem de 8% do peso corporal (PC), com base na matéria seca de folhas verdes. Foram utilizados 24 novilhos: 12 da raça Nelore (386 kg PCJ) e 12 mestiços ½Limousin-Nelore (397 kg PCJ). As mudanças de composição corporal no período de 104 dias foram avaliadas pelo método do abate comparativo. Após o abate, foram pesados todos os componentes corporais e coletadas, processadas e analisadas quimicamente amostras representativas da carcaça (seção HH) e dos tecidos não-componentes da carcaça, visando estimar os conteúdos corporais de proteína, gordura e energia em cada animal. Foram ajustadas equações alométricas linearizadas para descrever o padrão de crescimento dos componentes corporais em função do peso de corpo vazio dos animais. As equações obtidas foram derivadas objetivando a predição das exigências líquidas de proteína e energia para ganho de peso. Não houve diferenças entre os animais nelores e mestiços quanto à deposição de proteína. Os animais nelores tenderam à maior deposição de energia no ganho em comparação aos mestiços. É possível obter carcaças bem acabadas em bovinos nelores e mestiços de maior porte em pastagens tropicais com oferta adequada de folhas.

The objective of this work was to evaluate body composition and net requirements of protein and energy for weight gain of Nellore and crossbred F1 Limousin-Nellore steers finished on Mombasa grass pastures. Mombasa grass (Panicum maximum) pastures were managed under intermitent stocking during the rainy season, with a forage offer of 8% of the body weight (BW) based on the dry matter of green leaves. Twenty-four steers were used: 12 were Nellore (386 kg SBW) and 12 were F1 Limousin-Nellore (397 kg SBW). Changes in body composition in a 104-day experimental period were evaluated according to the comparative slaughter method. After slaughter, all body components were weighed and representative samples of carcass (HH section) and non-carcass tissues were collected, processed and chemically analyzed to determine body contents of protein, fat and energy in each animal. Linearized allometric equations were fitted to describe the pattern of growth of body components as a function of empty body weight of the animals. The obtained equations were derived to predict net requirements of protein and energy for weight gain. There were no differences between Nellore and crossbreed steers regarding to protein deposition. Nellore animals tended to a greater deposition of energy on weight compared to crossbred animals. It is possible to obtain well finished carcass in Nellore and crossbred steers with a greater weight on tropical pastures with an adequate supply of leaves.

Activation of 5-hydroxytryptamine (5-HT) 5-HT1A, 5-HT2C, 5-HT3, and 5-HT7 receptors modulates the excitability of cardiac vagal motoneurones, but the precise role of 5-HT2A/2B receptors in these phenomena is unclear. We report here the effects of intracisternal (ic) administration of selective 5-HT2A/2B antagonists on the vagal bradycardia elicited by activation of the von Bezold-Jarisch reflex with phenylbiguanide. The experiments were performed on urethane-anesthetized male Wistar rats (250-270 g, N = 7-9 per group). The animals were placed in a stereotaxic frame and their atlanto-occipital membrane was exposed to allow ic injections. The rats received atenolol (1 mg/kg, iv) to block the sympathetic component of the reflex bradycardia; 20-min later, the cardiopulmonary reflex was induced with phenylbiguanide (15 µg/kg, iv) injected at 15-min intervals until 3 similar bradycardias were obtained. Ten minutes after the last pre-drug bradycardia, R-96544 (a 5-HT2A antagonist; 0.1 µmol/kg), SB-204741 (a 5-HT2B antagonist; 0.1 µmol/kg) or vehicle was injected ic. The subsequent iv injections of phenylbiguanide were administered 5, 20, 35, and 50 min after the ic injection. The selective 5-HT2A receptor antagonism attenuated the vagal bradycardia and hypotension, with maximal effect at 35 min after the antagonist (pre-drug = -200 ± 11 bpm and -42 ± 3 mmHg; at 35 min = -84 ± 10 bpm and -33 ± 2 mmHg; P < 0.05). Neither the 5-HT2B receptor antagonists nor the vehicle changed the reflex. These data suggest that central 5-HT2A receptors modulate the central pathways of the parasympathetic component of the von Bezold-Jarisch reflex.

RESUMO Foram analisados soros de 163 equídeos (143 equinos e 20 muares) provenientes de 16 municípios do sul do Estado de São Paulo, parte no Vale do Ribeira e parte no litoral. Utilizouse uma amostra probabilística estratificada em dois estágios, sendo a unidade amostral de primeiro estágio constituída pela unidade de produção agropecuária (UPA) e a de segundo estágio pelo animal dentro da UPA sorteada. Os soros foram coletados no período de outubro de 2004 a junho de 2005. Foram estimadas as prevalências de anticorpos contra os vírus das encefalites equinas do tipo leste (EEE), oeste (WEE) e venezuelana (VEE), herpesvírus equino (HVE), arterite viral dos equinos (AVE), influenza equina 1 e 2 (IE-1 e 2) e estomatite vesicular Indiana 2 – Cocal (COCV) e Indiana 3 – Alagoas (VSAV). Foram utilizadas as técnicas de inibição da hemoaglutinação para a detecção de anticorpos contra os vírus IE-1 e 2 e de soroneutralização para os demais vírus estudados. Dos animais testados, 26% apresentaram anticorpos contra o HVE, 21% para COCV, 5% para VSAV, 16% para EEE, 2,26% para VEE, 11% para influenza Equi/2 e 2,7% para influenza Equi/1. Não se encontraram animais reagentes para WEE e AVE. A soroprevalência obtida sugere a circulação do HVE, dos vírus da IE Equi-1(H7N7) e Equi-2 (H3N8), dos vírus EEE e VEE e dos vírus da estomatite vesicular Indiana 2 – Cocal (COCV) e Indiana 3 – Alagoas (VSAV) no rebanho de equídeos do sul do Estado de São Paulo.

ABSTRACT Sera from 163 Equidae (143 equines and 20 mules) from 16 municipalities in the southern region of São Paulo State, Brazil, were selected in a two-stage stratified probabilistic sample survey. Serum samples were collected from October 2004 to June 2005. The antibody prevalence was estimated against eastern (EEE), western (WEE) and Venezuelan (VEE) equine encephalitis, equine herpesvirus (EHV), equine viral arteritis (EVA), equine influenza 1 and 2 (EI– 1 and 2) and vesicular stomatitis (Indiana 2 Cocal virus – COCV and Indiana 3 – Alagoas virus (VSAV). The results showed positivity of 26% for EHV, 21% for COCV, 5% for VCAV, 16% for EEE, 2.26% for VEE, 11% for influenza Equi/2 and 2.7% for influenza Equi/1. No antibodies were detected against WEE and AVE. These results suggest that the equine population in the south of São Paulo State is exposed to infection risk of HVE, IE Equi-1(H7N7) and Equi-2 (H3N8), EEE, VEE and Indiana 2 – Cocal (COCV) Indiana 3 – Alagoas (VSAV).

Avaliaram-se e classificaram-se por meio da vídeo-artroscopia as alterações da articulação fêmoro-tíbio-patelar (FTP), 21 dias após secção experimental do ligamento cruzado cranial (LCCr) em cães, tendo como referência os parâmetros encontrados no exame artroscópico imediatamente anterior à secção. Ao exame artroscópico, foi possível visibilizar os cotos remanescentes do LCCr e as alterações articulares, como aumento da vascularização, aumento das vilosidades na membrana sinovial, bem como fibrilação e osteófitos, principalmente nas bordas trocleares do fêmur. Os resultados sugerem que a artroscopia é um método preciso de avaliação macroscópica dos tecidos articulares moles e duros.

By the use of videoarthroscopy, the changes of the stifle joint after experimental rupture of cranial cruciate ligament (CCL) in dogs were evaluated and classified, based on the parameters found at the arthroscopic examination right before the rupture. By the arthroscopic examination, it was possible to visualize the remainings of the CCL and joint changes such as increase of the vascularity and synovial proliferation increase in the synovial membranes, as well as fibrillation and irregularities on the joint surfaces and osteophyte formation, mainly on the trochlear ridges. The results suggest that arthroscopy is a precise method for macroscopic evaluation of the smooth and bone joint tissues

It is well known that the ventrolateral medulla contains neurons involved in the tonic and reflex control of the cardiovascular system. Two regions within the ventrolateral medulla were initially identified: the rostral ventrolateral medulla (RVLM) and the caudal ventrolateral medulla (CVLM). Activation of the RVLM raises arterial blood pressure and sympathetic nerve activity, and activation of the CVLM causes opposite effects. The RVLM premotor neurons project directly to sympathetic preganglionic neurons and are involved in the maintenance of resting sympathetic vasomotor tone. A significant proportion of tonic activity in the RVLM sympathetic premotor neurons is driven by neurons located in a third region of the ventrolateral medulla denominated caudal pressor area (CPA). The CPA is a pressor region located at the extreme caudal part of the ventrolateral medulla that appears to have an important role controlling the activity of RVLM neurons. In this brief review, we will address the importance of the ventrolateral medulla neurons for the generation of resting sympathetic tone related to arterial blood pressure control focusing on two regions, the RVLM and the CPA.

Pressor responses elicited by stimulation of the nucleus raphe obscurus (NRO) depend on the integrity of the rostral ventrolateral medulla (RVLM). Therefore, to test the participation of excitatory amino acid (EAA) receptors in the cardiovascular responses evoked by NRO stimulation (1 ms, 100 Hz, 40-70 µA, for 10 s), the EAA antagonist kynurenic acid (Kyn) was microinjected at different sites in the ventrolateral medullar surface (2.7 nmol/200 nl) of male Wistar rats (270-320 g, N = 39) and NRO stimulation was repeated. The effects of NRO stimulation were: hypertension (deltaMAP = +43 ± 1 mmHg, P<0.01), bradycardia (deltaHR = -30 ± 7 bpm, P<0.01) and apnea. Bilateral microinjection of Kyn into the RVLM, which did not change baseline parameters, almost abolished the bradycardia induced by NRO stimulation (deltaHR = -61 ± 3 before vs -2 ± 3 bpm after Kyn, P<0.01, N = 7). Unilateral microinjection of Kyn into the CVLM did not change baseline parameters or reduce the pressor response to NRO stimulation (deltaMAP = +46 ± 5 before vs +48 ± 5 mmHg after Kyn, N = 6). Kyn bilaterally microinjected into the caudal pressor area reduced blood pressure and heart rate and almost abolished the pressor response to NRO stimulation (deltaMAP = +46 ± 4 mmHg before vs +4 ± 2 mmHg after Kyn, P<0.01, N = 7). These results indicate that EAA receptors on the medullary ventrolateral surface play a role in the modulation of the cardiovascular responses induced by NRO stimulation, and also suggest that the RVLM participates in the modulation of heart rate responses and that the caudal pressor area modulates the pressor response following NRO stimulation.

The role of the caudal pressor area (CPA) in the maintenance of vasomotor tonus in anesthetized and decerebrate animals has been clearly established. In conscious animals, however, the participation of CPA in the cardiovascular control remains to be fully elucidated. In the present study, unilateral L-glutamate (L-Glu) (10 and/or 20 nmol/70 nl) microinjection into CPA, in conscious male Wistar rats (250-280 g) caused a significant increase in mean arterial blood pressure (MAP; control: 112 ± 1.9 mmHg; after 20 nmol L-Glu: 139 ± 4.5 mmHg, N = 12, P<0.05) and respiratory rate (control: 81 ± 3.5 breaths/min; after 10 nmol L-Glu: 92 ± 3 breaths/min, P<0.05; after 20 nmol L-Glu: 104 ± 5 breaths/min, N = 6, P<0.05). The subsequent anesthesia with urethane caused a significant increase in basal respiratory frequency (conscious: 81 ± 3.5 breaths/min; under urethane: 107 ± 1.3 breaths/min, N = 6, P<0.05). Anesthesia also significantly attenuated L-Glu-evoked pressor (conscious: deltaMAP = +27 mmHg; anesthetized: deltaMAP = +18 mmHg, P<0.05) and respiratory responses. These results suggest that glutamatergic receptors in the CPA are involved in cardiovascular and respiratory modulation in conscious rats.