Cardiovascular control in the human is significantly impaired after spinal cord injury(SCI) having a direct effect on the sympathetic nervous system (SNS) causing an inability toregulate vasoconstriction below the level of the lesion. The effects of SCI on the two majorcomponents of blood pressure regulation, control of plasma volume and neural control of theheart and peripheral vasculature are poorly understood. In particular, no index to diagnosedisorders to autonomic control of the heart and vasculature has been developed. The presentstudy primarily utilized noninvasively acquired, easily accessible variables that may havepromise as indicators of autonomic activity for assessing the level of autonomic injury andrecovery of visceral control following SCI. The most significant results and the clearestdifferences between the three groups (able-bodied, paraplegic and tetraplegic) were evident inspectral analysis obtained in the frequency domain: Arterial blood pressure and lower body (at aregion on the shin) skin perfusion spectral power in the low frequency (LF) region are ofsignificance. These variables could be good discriminators of the three groups, as well as showlevel of SCI and autonomic function.

No description available.

L’activité neurovégétative est un corrélat de la charge mentale et émotionnelle, même lorsque les stimulations sontbrèves et de faible intensité. Elle est notamment sensible à la difficulté perçue mais aussi à une forme particulièred’induction affective, l’injustice. Par conséquent, nous avons utilisé ces mesures neurovégétatives comme variablesdépendantes de la charge mentale/émotionnelle subie par les conducteurs automobiles, dans des conditions plus oumoins astreignantes.Un freinage appuyé induit des réponses neurovégétatives longues et amples, corrélat d’une charge importante. Lafocalisation de l’attention est élevée dans des situations de conduite stressantes, nécessaire pour répondre auchangement possible de la couleur d’un feu tricolore.Nous avons montré, à partir d’enregistrements magnétoencéphalographiques, que sous forte contrainte temporelle,les conducteurs qui avaient tendance à enfreindre les feux présentaient une activation plus élevée au niveau ducortex dorsolatéral gauche. Ils opéraient en permanence un compromis entre le respect simultané du code de laroute et des consignes expérimentales ce qui complexifiait la sélection de la réponse motrice.L’activité végétative s’avère être un témoin fiable de l’activité centrale. L’activation du cortex cingulaire antérieurgauche semble être à l’origine d’une diminution de l’activité électrodermale et cardiaque.Du fait de l’altération de leurs capacités cognitives, les seniors pourraient devenir anxieux face à des situations deconduite pourtant considérées comme anodines pour les plus jeunes. Il est nécessaire de leur dispenser desrecommandations simples afin qu’ils abordent la route plus sereinement. / Autonomic activity is a correlate of mental and emotional load, even when stimulations are brief and of low intensity.This activity is especially sensitive to the perceived difficulty, but also to a particular form of emotional induction, theinjustice. Therefore, we used these autonomic measures as dependent variables of mental/emotional loadundergone by drivers, under more or less demanding conditions.A heavy braking elicited long and ample autonomic responses, correlate of a strong load. The focus of attention wasgreater in stressful driving conditions, needed to get ready to respond to the possible change of the color of thetraffic light.We showed, from magnetoencephalographic recordings, that under high time pressure, drivers who tended to breakthe lights showed higher activation in the left dorsolateral prefrontal cortex. They continuously operated a trade-offbetween the simultaneous respect of the traffic law and of the experimental instructions thus making the motorresponse selection harder.We also evidenced that the autonomic activity reliably paralleled the central activity. The activation of the leftanterior cingulate cortex decreased both electrodermal and cardiac activities.Due to their impaired cognitive abilities, ageing citizens might become anxious during driving situations consideredbenign by young drivers. It is necessary to provide them simple recommendations in order that they address the roadmore serenely.

Stress and monotonous work contribute substantially to the development of chronic musculoskeletal disorders. Yet, the pathophysiological mechanisms underlying the process, particularly the involvement of autonomic regulation, remain unclear. It has been suggested that altered motor control resulting from distorted sensory information from fatigued muscles may be an important component in the development of musculoskeletal disorders. Animal studies have shown that sympathetic nervous system activation exerts actions in skeletal muscles, such as vasoconstriction and modulation of afferent information from muscle spindles. However, few attempts have been made to address this issue in humans. Therefore, the first aim of the thesis was to investigate the impact of repetitive computer work with and without additional stressors on muscle oxygenation and position sense in the upper extremity. Assuming an important role of stress in the development of chronic musculoskeletal symptoms, one may expect open or latent manifestations of such symptoms in patients with non-specific stress-related illnesses. It is possible that sympathetic activation may influence pain perception, and that treatments aimed at reducing stress may also affect the pain experience. Thus, the second aim of the thesis was to evaluate the effects of a cognitive-behavioral training program and a physical activity program for patients with stress-related illnesses on autonomic reactivity, pain, and perceived health. First, a laboratory model of computer mouse use was characterized in terms of biomechanical exposure of the wrist, and wrist position sense was determined before and after 45 minutes of continuous mouse use. Then, the effects of performing the computer mouse work under time pressure and precision demands were determined. Autonomic activity and muscle oxygenation in the upper extremity were measured during the work, and wrist position sense was assessed before and after the work. When patients with stress-related illnesses were compared to healthy individuals in autonomic reactivity to functional tests, pressure-pain thresholds, and ratings of health, indications of a relation between autonomic reactivity and symptoms of pain was found. Hence, in a subsequent evaluation of a cognitive-behavioral training program and a physical activity program for patients with stress-related illnesses, post intervention effects on autonomic reactivity to functional tests, pressure-pain thresholds, ratings of health and return-to-work were studied during a period of 12 months after the intervention. The main findings were the following. 1) Wrist kinetics data obtained during the computer mouse work showed similarities to previously presented data for mouse-operated design tasks. 2) When time pressure and precision demands were added to the computer work, increased autonomic activity paralleled with decreased muscle oxygenation in the upper extremity was found. Wrist position sense accuracy, however, did not decrease after the work as it did when the work was performed without the additional demands. The result is intriguing, as it does not appear to be in concordance with previous animal studies. 3) Patients with stress-related illnesses showed higher autonomic reactivity to cognitive and physical laboratory tests than healthy control subjects. They also had substantially lower pressure-pain thresholds in the back, and rated poorer health and health-related behavior than the control subjects. 4) We found little difference in effect of cognitive-behavioral training and physical activity, compared to usual care, for patients with stress-related illnesses. Patients in the control group showed an improvement of about the same magnitude as in the treatment groups over the 12-month follow-up period. The present findings indicate a non-additive relation between autonomic activity during repetitive work and position sense inaccuracy. Furthermore, patients with stress-related illnesses often reported pain in the neck, shoulders, and lower back. This was associated with lower pressure-pain thresholds in the back and a modest increase in sympathetic reactivity to physical and mental tests, which might suggest a potential use of these methods in the clinical examination and rehabilitation of patients with stress-related illnesses.

Submitted by Livia Mello (liviacmello@yahoo.com.br) on 2016-10-03T13:24:24Z No. of bitstreams: 1 DissLGS.pdf: 2043932 bytes, checksum: 2dbd0889b9f3fb31e59390124abd82bd (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-04-24T19:29:15Z (GMT) No. of bitstreams: 1 DissLGS.pdf: 2043932 bytes, checksum: 2dbd0889b9f3fb31e59390124abd82bd (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-04-24T19:29:21Z (GMT) No. of bitstreams: 1 DissLGS.pdf: 2043932 bytes, checksum: 2dbd0889b9f3fb31e59390124abd82bd (MD5) / Made available in DSpace on 2017-04-24T19:39:20Z (GMT). No. of bitstreams: 1 DissLGS.pdf: 2043932 bytes, checksum: 2dbd0889b9f3fb31e59390124abd82bd (MD5) Previous issue date: 2016-03-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The endocannabinoid neurotransmission has been reported as an important neurochemical mechanism involved in behavioral and physiological responses to stress. Previous studies provided evidence of endocannabinoid release in the bed nucleus of the stria terminalis (BNST) during aversive stimuli. Nevertheless, a possible involvement of this neurochemical mechanism in stress responses has never been evaluated. Therefore, in the present study we investigated the involvement of endocannabinoid neurotransmission within the BNST, acting via local CB1 receptor, in cardiovascular responses evoked by acute restraint stress in rats. We found that microinjection of the selective CB1 receptor antagonist AM251 (1, 30, and 100 pmol/100 nL) into the BNST enhanced the heart rate increase caused by restraint stress, without affecting the arterial pressure increase and the sympathetic-mediated cutaneous vasoconstriction response. Conversely, increase in endogenous levels of anandamide in the BNST evoked by local treatment with the fatty acid amide hydrolase (FAAH) enzyme inhibitor URB597 (30 pmol/100 nL) decreased restraint-evoked tachycardia. Inhibition of the hydrolysis of 2-arachidonoylglycerol (2-AG) in the BNST by local microinjection of the monoacylglycerol lipase (MAGL) enzyme inhibitor JZL184 (30 pmol/100 nL) also decreased the HR response to restraint. Effects of BNST treatment with either URB597 or JZL184 were inhibited by local pretreatment with the CB 1 receptor antagonist AM251. These findings indicate an involvement of BNST endocannabinoid neurotransmission, acting via CB1 receptor, in cardiovascular adjustments during emotional stress. Furthermore, present findings provide evidence that this control may be mediated by local release of either anandamide or 2-AG. / A neurotransmissão endocanabinóide tem sido reportada como um importante mecanismo neuroquímico envolvido em respostas comportamentais e fisiológicas ao estresse. Estudos anteriores forneceram evidências da liberação de endocanabinóides no núcleo leito da estria terminal (NLET) durante os estímulos aversivos. No entanto, um possível envolvimento deste mecanismo neuroquímico do NLET nas respostas ao estresse nunca foi investigada. Portanto, no presente estudo nós investigamos o envolvimento da neurotransmissão endocanabinóide no NLET, agindo via receptor CB1 local, nas respostas cardiovasculares desencadeadas pelo estresse de restrição agudo em ratos. A microinjeção de AM251 (antagonista seletivo do receptor CB1) (1, 30 e 100 pmol/100 nL) no NLET aumentou a resposta de taquicardia causada pelo o estresse de restrição agudo, sem afetar as respostas de aumento da pressão arterial e a de vasoconstrição cutânea. Por outro lado, o aumento dos níveis endógenos do endocanabinóide anandamida (AEA) no NLET causado pelo tratamento local com URB597 (inibidor da enzima ácido graxo amino hidrolase -FAAH) (30 pmol/100 nL) atenuou o aumento da frequência cardíaca desencadeada pelo o estresse de restrição agudo. O aumento nos níveis locais de 2-araquidonoilglicerol (2-AG) no NLET causado pelo tratamento local com JZL184 (inibidor da enzima monoacilglicerol lipase - MAGL) (30 pmol/100 nL) também reduziu a resposta taquicárdica desencadeada pelo o estresse de restrição agudo. Os efeitos tanto do URB597 quanto do JZL184 foram abolidos após o pré-tratamento local do NLET com o antagonista seletivo do receptor CB1 (AM251). Estes resultados indicam um envolvimento da neurotransmissão endocanabinóide no NLET, agindo via receptor CB1 , nos ajustes cardiovasculares durante o estresse emocional. Além disso, nossos achados fornecem evidências de que este controle pode ser mediado pela liberação local tanto de anandamida quanto de 2-AG.

Made available in DSpace on 2016-06-02T19:23:01Z (GMT). No. of bitstreams: 1 6296.pdf: 1076560 bytes, checksum: cad1771b913c86aea11893b93efbc169 (MD5) Previous issue date: 2014-09-05 / Financiadora de Estudos e Projetos / Here we compared effects of chronic treatment with the preferential nNOS inhibitor 7- nitroindazole (7-NI) with those evoked by the conventional antidepressant fluoxetine on alterations taken as markers of depression (immobility in the forced swimming test(FST), decreased body weight gain, and increased plasma corticosterone) and cardiovascular changes evoked by the chronic variable stress (CVS) in rats. For this, male rats were exposed to a 14- days CVS protocol while being concurrently treated with either 7-NI or fluoxetine. Fluoxetine and 7-NI prevented increased immobility in the FST induced by CVS and reduced plasma corticosterone in stressed rats. Both treatments also prevented CVS-evoked reduction on depressor response to vasodilator agents and baroreflex changes. Nevertheless, none of pharmacological treatments affected body weight reduction induced by CVS. Furthermore, fluoxetine reduced body weight gain in unstressed animals. Fluoxetine and nNOS blockade also induced cardiovascular changes independent of stress exposure, including increase on cardiac parasympathetic tone, intrinsic heart rate, and vascular sympathetic modulation; reduction in sympathetic activity to the heart and the pressor response to vasoconstrictor agents, and impairment of baroreflex activity. These findings provide evidence that both fluoxetine and 7-NI prevent depression-like behavioural changes and cardiovascular dysfunctions associated with CVS. Furthermore, both pharmacological treatments caused cardiovascular changes that were independent of stress exposure, some being beneficial and other potentially increasing vulnerability to development of cardiovascular diseases. Nevertheless, the body weight reduction induced by fluoxetine treatment is especially important considering the weight loss related to depression. / No presente estudo nós comparamos os efeitos do tratamento crônico com 7-nitroindazole (7- NI) (inibidor preferencial da nNOS) com aqueles evocados pelo antidepressivo convencional fluoxetina sobre as respostas do tipo depressivas (imobilidade no teste de natação forçada (TNF), diminuição do ganho de peso corporal e aumento da corticosterona plasmástica) e as alterações cardiovasculares provocadas pelo estresse crônico variável (ECV) em ratos. Para isso, ratos Wistar foram expostos a um protocolo de ECV por 14 dias, e tratados concomitantemente com 7-NI ou fluoxetina. A fluoxetina e o 7-NI impediram o aumento da imobilidade no TNF induzida pelo ECV e reduziu a corticosterona plasmática nos ratos estressados. Ambos os tratamentos também inibiram a redução evocada pelo ECV nas respostas depressoras a agentes vasodilatadores e as mudanças na atividade do barorreflexo. No entanto, nenhum dos tratamentos farmacológicos afetaram a redução do peso corporal induzida pelo ECV. Além disso, a fluoxetina reduziu o ganho de peso nos animais controle. A fluoxetina e o bloqueio da nNOS também induziram alterações cardiovasculares independente da exposição ao estresse, que incluíram: aumento no tônus parassimpático cardíaco, frequência cardíaca intrínseca e modulação simpática vascular; redução da atividade simpática para o coração e da resposta pressora a agentes vasoconstritores e diminuição da atividade do barorreflexo. Estes resultados fornecem evidências de que a fluoxetina e o 7-NI previnem as alterações comportamentais do tipo depressivas e as disfunções cardiovasculares associados ao ECV. Além disso, ambos os tratamentos farmacológicos causaram alterações cardiovasculares independentes de exposição ao estresse, sendo algumas benéficas e outras potencialmente aumentando a vulnerabilidade para o desenvolvimento de doenças cardiovasculares. No entanto, a redução de peso corporal induzida pelo tratamento com fluoxetina é especialmente importante, considerando a perda de peso relacionada com a depressão.