Control of breathing and blood pressure by parafacial neurons in conscious rats

New Findings: • What is the central question of this study? The main purpose of the present manuscript was to investigate the cardiorespiratory responses to hypoxia or hypercapnia in conscious rats submitted to neuronal blockade of the parafacial region. We clearly showed that the integrity of parafacial region is important for the respiratory responses elicited by peripheral and central chemoreflex activation in freely behavior rats. • What is the main finding and its importance? Since the parafacial region is part of the respiratory rhythm generator, they are essential for postnatal survival, which is probably due to their contribution to chemoreception in conscious rats. The retrotrapezoid nucleus (RTN), located in the parafacial region, contains glutamatergic neurons that express the transcriptor factor Phox2b and that are suggested to be central respiratory chemoreceptors. Studies in anaesthetized animals or in vitro have suggested that RTN neurons are important in the control of breathing by influencing respiratory rate, inspiratory amplitude and active expiration. However, the contribution of these neurons to cardiorespiratory control in conscious rats is not clear. Male Holtzman rats (280-300 g, n= 6-8) with bilateral stainless-steel cannulae implanted into the RTN were used. In conscious rats, the microinjection of the ionotropic glutamatergic agonist NMDA (5 pmol in 50 nl) into the RTN increased respiratory frequency (by 42%), tidal volume (by 21%), ventilation (by 68%), peak expiratory flow (by 24%) and mean arterial pressure (MAP, increased by 16 ± 4, versus saline, 3 ± 2 mmHg). Bilateral inhibition of the RTN neurons with the GABAA agonist muscimol (100 pmol in 50 nl) reduced resting ventilation (52 ± 34, versus saline, 250 ± 56 ml min-1 kg-1 with absolute values) and attenuated the respiratory response to hypercapnia and hypoxia. Muscimol injected into the RTN slightly reduced resting MAP (decreased by 13 ± 7, versus saline, increased by 3 ± 2 mmHg), without changing the effects of hypercapnia or hypoxia on MAP and heart rate. The results suggest that RTN neurons activate facilitatory mechanisms important to the control of ventilation in resting, hypoxic or hypercapnic conditions in conscious rats. © 2012 The Authors. Experimental Physiology © 2012 The Physiological Society.

Resting heart rate: Its correlations and potential for screening metabolic dysfunctions in adolescents

Background: In pediatric populations, the use of resting heart rate as a health index remains unclear, mainly in epidemiological settings. The aims of this study were to analyze the impact of resting heart rate on screening dyslipidemia and high blood glucose and also to identify its significance in pediatric populations.Methods: The sample was composed of 971 randomly selected adolescents aged 11 to 17 years (410 boys and 561 girls). Resting heart rate was measured with oscillometric devices using two types of cuffs according to the arm circumference. Biochemical parameters triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and glucose were measured. Body fatness, sleep, smoking, alcohol consumption and cardiorespiratory fitness were analyzed.Results: Resting heart rate was positively related to higher sleep quality (β = 0.005, p = 0.039) and negatively related to cardiorespiratory fitness (β = -0.207, p = 0.001). The receiver operating characteristic curve indicated significant potential for resting heart rate in the screening of adolescents at increased values of fasting glucose (area under curve = 0.611 ± 0.039 [0.534 - 0.688]) and triglycerides (area under curve = 0.618 ± 0.044 [0.531 - 0.705]).Conclusion: High resting heart rate constitutes a significant and independent risk related to dyslipidemia and high blood glucose in pediatric populations. Sleep and cardiorespiratory fitness are two important determinants of the resting heart rate. © 2013 Fernandes et al.; licensee BioMed Central Ltd.

Age Affects Exercise-Induced Improvements in Heart Rate Response to Exercise

The aim of the present study was to analyze the effects of age on cardiorespiratory fitness (CRF), muscle strength and heart rate (HR) response to exercise adaptation in women in response to a long-term twice-weekly combined aerobic and resistance exercise program. 85 sedentary women, divided into young (YG; n=22, 30.3±6.2 years), early middle-aged (EMG; n=28, 44.1±2.5 years), late middle-aged (LMG; n=20, 56.7±3.5 years) and older (OG; n=15, 71.4±6.9 years) groups, had their CRF, muscle strength (1-repetition maximum test) and HR response to exercise (graded exercise test) measured before and after 12 months of combined exercise training. Exercise training improved CRF and muscle strength in all age groups (P<0.05), and no significant differences were observed between groups. Exercise training also improved resting HR and recovery HR in YG and EMG (P<0.05), but not in LMG and OG. Maximal HR did not change in any group. Combined aerobic and resistance training at a frequency of 2 days/week improves CRF and muscle strength throughout the lifespan. However, exercise-induced improvements in the HR recovery response to exercise may be impaired in late middle-aged and older women. © Georg Thieme Verlag KG.

Uso da lidocaína isolada ou associada à quetamina ou ao butorfanol, em anestesia epidural em cães: avaliação cardiorrespiratória e analgésica

Pós-graduação em Anestesiologia - FMB

Avaliação da metadona e do tramadol sobre analgesia pós-operatória e parâmetros clínicos de cadelas submetidas a ovarioisterectomias e mastectomias

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos da hidratação sobre a modulação autonômica e parâmetros cardiorrespiratórios durante e após exercício físico de longa duração

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos do exercício prévio de intensidade supramáxima sobre a cinética do consumo de oxigênio em ciclistas treinados

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Impacto genético e ambiental na aptidão cardiorrespiratória, atividade física e metabolismo de glicose

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparação de parâmetros cardiorrespiratórios em testes indiretos e diretos de avaliação funcional em indivíduos saudáveis e diabéticos

Pós-graduação em Ciências da Motricidade - IBRC

Efeitos cardiorrespiratórios e motilidade gastrointestinal da infusão contínua de butorfanol em equinos anestesiados pelo isofluorano

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

Obesidade sarcopênica: diagnóstico, prevalência e associações com aptidão física, resistência insulínica, estresse inflamatório e oxidativo

Pós-graduação em Patologia - FMB

Uso do isofluorano em veados-catingueiro (Mazama gouazoubira) pré- tratados com diferentes protocolos de contenção química

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo cardiorrespiratório comparativo da anestesia geral inalatória com o sevofluorano em cadela não-gestantes e no terço final da gestação, pré-tratados com acepromazina e propofol

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

Estudo comparativo entre parto normal e a anestesia para a cesariana em cães: estudo clínico e cardiorrespiratório na mãe e no feto

Pós-graduação em Medicina Veterinária - FMVZ

Avaliação da associação propofol e de cloridrato de alfentamil na manutenção anestésico por infusão intravenosa contínua em cães após medicação pré-anestésica com acepromazina

Pós-graduação em Medicina Veterinária - FMVZ