Presente y futuro de la estimulación magnética transcraneal / Present and future of the transcranial magnetic stimulation

La estimulación magnética transcraneal ha llamado la atención de neurocientíficos y público en general por la posibilidad de estimular y “controlar” el sistema nervioso de forma no invasiva, realizar diagnósticos más exactos, y aplicar tratamientos y programas de rehabilitación más efectivos en múltiples enfermedades que afectan el sistema nervioso. Así mismo, esta novedosa herramienta ha ayudado a develar la complejidad del comportamiento neural, sus conexiones y su modulación plástica. La estimulación magnética aplicada de manera simple o pareada, se ha convertido en una alternativa útil en el diagnóstico de enfermedades como esclerosis múltiple, enfermedad de Parkinson, epilepsia, distonía, esclerosis lateral amiotrófica, enfermedad cerebro vascular, así como el sueño y sus trastornos, entre otras alteraciones. A nivel terapéutico, se ha sugerido el uso de la estimulación magnética repetitiva con diferentes niveles de evidencia en depresión refractaria a tratamiento farmacológico convencional, tinitus, afonía psicógena, enfermedad de Alzheimer, autismo, enfermedad de Parkinson, distonías, accidente cerebro vascular, epilepsia, trastornos de ansiedad generalizada, estrés post-traumático, alucinaciones auditivas, dolor crónico, afasias, trastorno obsesivo compulsivo, disquinesias inducidas por L-Dopa, manía y síndrome de Rasmussen, entre otros trastornos. Su beneficio en neurorehabilitación es una realidad inocultable, en cuyo caso se ha podido usar con efectividad y, prácticamente, sin efectos secundarios.

Magnetic stimulation has called the attention of neuroscientists and the public due to the possibility to stimulate and “control” the nervous system in a non-invasive way. It has helped to make more accurate diagnosis, and apply more effective treatments and rehabilitation protocols in several diseases that affect the nervous system. Likewise, this novel tool has increased our knowledge about complex neural behavior, its connections as well as its plastic modulation. Magnetic stimulation applied in simple or paired-pulse protocols is a useful alternative in the diagnosis of diseases such as multiple sclerosis, Parkinson disease, epilepsy, dystonia, amyotrophic lateral sclerosis, cerebrovascular disease, and sleep disorders. From the therapeutic perspective, magnetic stimulation applied repetitively has been found useful, with different degrees of efficacy, in treating resistant depression, tinnitus, psychogenic dysphonia, Alzheimer disease, autism, Parkinson disease, dystonia, stroke, epilepsy, generalized anxiety as well as post traumatic stress disorder, auditory hallucinations, chronic pain, aphasias, obsessive-compulsive disorders, L-dopa induced dyskynesia, mania and Rasmussen syndrome, among others. The potential of magnetic stimulation in neurorehabilitation is outstanding, with excellent range of safety and, in practical terms, without side effects.

Quimiossensibilidade durante exercício na insuficiência cardíaca: respostas ventilatórias, cronotrópicas e neurohormonais / Exercise chemosensitivity in heart failure: ventilatory, chronotropic and neurohormonal responses / Quimiosensibilidad durante ejercicio en la insuficiencia cardíaca: respuestas ventilatorias, cronotrópicas y neurohormonales

FUNDAMENTO: Insuficiência cardíaca (IC) está associada com aumento da quimio-sensibilidade periférica e central em repouso, que pode estar correlacionada com um aumento na resposta ventilatória durante exercício. Entretanto, SUS sensibilidade na IC durante o exercício ainda não foi reportada. OBJETIVO: Testar se o estímulo dos quimiorreceptores centrais e periféricos em pacientes com IC pode modular respostas ventilatórias, cronotrópicas e neurohormonais durante exercício submáximo. MÉTODOS: Investigamos a quimio-sensibilidade central e periférica em 15 pacientes com insuficiência cardíaca (IC) e 7 controles normais (C), comparando a resposta durante 3 testes de caminhada de 6 minutos (TC6M), realizado em esteira ergométrica com: ar ambiente, em hipóxia e em hipercapnia (em ordem randômica). RESULTADOS: FR em ar ambiente nos grupos C e IC foi 17±2 e 22±2 (p<,0001); em hipóxia, foi 17±1 e 23±2 (p<,02); com CO25 por cento foi 20±2 e 22±5 (p<,02). Volume tidal (VT) ou corrente em ar ambiente foi 1,25±0,17 e 1,08±0,19 (p<,01); em hipóxia 1,65±0,34 e 1,2±0,2(p<,0001); com CO25 por cento 1,55±0,46 e 1,29±0,39 (p<,0001). Em repouso, o aumento na IC foi maior para VE (C 33±40 por cento, IC 62±94 por cento, p<,01), FC(C 7±10 por cento, IC 10±10 por cento, p<0,05) em repouso. Durante a hipóxia, o aumento durante o exercício na IC foi maior para FR (C 1±4, IC 11±6,p<,05), FC (C 12±2, IC 14±3, p<,05), VE/VO2 (C -4±18 por cento, IC 24±21 por cento, p<,01), FC/VO2 (C -26±11 por cento, IC 11±5 por cento, p<,01), VE/DC (C 36±10 por cento, 46±14, p<,05 por cento ) and FC/DC (C 18±8 por cento, HF 29±11, p<,01). Durante exercício em hipóxia no grupo IC, o NO diminuiu e os níveis de IL-6 e aldosterona aumentaram. Os níveis neurohormonais permaneceram inalterados no grupo C. CONCLUSÃO: A quimio-sensibilidade central e a periférica durante o exercício estão aumentadas na IC e podem modular padrões respiratórios, cronotrópicos cardíacos e atividade neurohormonal durante exercício.

BACKGROUND: Heart failure (HF) is associated with resting increased peripheral and central chemosensitivity which may correlate with an increased ventilatory response to exercise. However, its sensitivity in HF during exercise was never really reported. OBJECTIVE: We tested if stimulation of central and peripheral chemoreceptors in HF patients could modulate ventilatory, chronotropic, and neurohormonal response during submaximal exercise. METHODS: We investigated central and peripheral chemosensitivity in 15 HF and 7 control (C) comparing response through three 6 minute walking tests conducted in a treadmill with : room air, hypoxia, and hypercapnia (in a randomic order). RESULTS: RR at room air C and HF was 17±2 and 22±2 (p<.0001); at hypoxia 17±1 and 23±2 (p<.02); at CO25 percent was 20±2 and 22±5 (p<.02). Tidal volume (TV) at room air was 1.25±0.17 and 1.08±0.19 (p<.01); at hypoxia 1.65±0.34 and 1.2±0.2 (p<.0001); at CO25 percent 1.55±0.46 and 1.29±0.39 (p<.0001). At rest the increment in HF was higher for VE (C 33±40 percent, HF 62±94 percent, p<.01), HR(C 7±10 percent, HF 10±10 percent, p<0.05) at rest. During hypoxia exercise increment in HF was higher for RR (C 1±4, HF 11±6,p<.05), HR (C 12±2, HF 14±3, p<.05), VE/VO2 (C -4±18 percent, HF 24±21 percent, p<.01), HR/VO2 (C -26±11 percent, HF 11±5 percent, p<.01), VE/WD (C 36±10 percent, 46±14, p<.05 percent) and HR/WD (C 18±8 percent, HF 29±11, p<.01). During HF hypoxia exercise NO reduced, and IL-6, aldosterone levels increased. Neurohormonal levels unchanged in C. CONCLUSION: Exercise peripheral and central chemosensitivity are increased in HF and may modulate respiratory pattern, cardiac chronotropic, and neurohormonal activity during exercise.

FUNDAMENTO: La insuficiencia cardíaca (IC) está asociada con aumento de la quimiosensibilidad periférica y central en reposo, que puede estar correlacionada con un aumento en la respuesta ventilatoria durante ejercicio. Mientras tanto, SUS sensibilidad en la IC durante el ejercicio aun no fue reportada. OBJETIVO: Verificar si el estímulo de los quimiorreceptores centrales y periféricos en pacientes con IC puede modular respuestas ventilatorias, cronotrópicas y neurohormonales durante ejercicio submáximo. MÉTODOS: Investigamos la quimiosensibilidad central y periférica en 15 pacientes con insuficiencia cardíaca (IC) y 7 controles normales (C), comparando la respuesta durante 3 tests de caminata de 6 minutos (TC6M), realizado en cinta ergométrica con: aire ambiente, en hipoxia y en hipercapnia (en orden randómico). RESULTADOS: FR en aire ambiente en los grupos C y IC fue 17±2 y 22±2 (p<,0001); en hipoxia, fue 17±1 y 23±2 (p<.02); con CO25 por ciento fue 20±2 y 22±5 (p<,02). Volumen tidal (VT) o corriente en aire ambiente fue 1,25±0,17 y 1,08±0,19 (p<,01); en hipoxia 1,65±0,34 y 1,2±0,2 (p<,0001); con CO25 por ciento 1,55±0,46 y 1,29±0,39 (p<,0001). En reposo, el aumento en la IC fue mayor para VI (C 33±40 por ciento, IC 62±94 por ciento, p<,01), FC(C 7±10 por ciento, IC 10±10 por ciento, p<0,05) en reposo. Durante la hipoxia, el aumento durante el ejercicio en la IC fue mayor para FR (C 1±4, IC 11±6, p<.05), FC (C 12±2, IC 14±3, p<.05), VI/VO2 (C -4±18 por ciento, IC 24±21 por ciento, p<.01), FC/VO2 (C -26±11 por ciento, IC 11±5 por ciento, p<.01), VI/DC (C 36±10 por ciento, 46±14, p<.05 por ciento) y FC/DC (C 18±8 por ciento, HF 29±11, p<.01). Durante ejercicio en hipoxia en el grupo IC, el NO disminuyó y los niveles de IL-6 y aldosterona aumentaron. Los niveles neurohormonales permanecieron inalterados en el grupo C. CONCLUSIÓN: La quimiosensibilidad central y la periférica durante el ejercicio están aumentadas en la IC y pueden modular estándares respiratorios, cronotrópicos cardíacos y actividad neurohormonal durante ejercicio.

Neurohormonal changes in medical students during academic srtess

Academic stress is a good model of psychological stress in humans and is thus useful for studying psychoneurohormonal changes. The aim of the current study was to examine the effect of academic examination stress on activation of the hypothalamus-autonomic nervous system [HANS] and the hypothalamic-pituitary-adrenocortical [HPA] axis, through the measurements of changes in neuro-hormones during final exams as compared to the pre-exam baseline. Forty-eight first- and second-year female medical students participated. Plasma leptin, neuropeptide Y [NPY], nitrite, nitrate, andrenomedullin, cortisol and adrenocorticotropic hormone [ACTH] were measured at baseline and during final examinations. Plasma levels of cortisol, ACTH, NPY, adrenomedullin, nitrite and nitrate increased during times of academic stress as compared to baseline levels. However, only plasma leptin level was decreased during the academic stress as compared to baseline, probably through a negative feedback mechanism resulting from sympathetic stimulation. The results indicate that both the HANS and HPA are involved in this type of stress and both are activated at the same time. Academic stress induced significant neurohormonal changes. Leptin, NPY, nitrite, nitrate, adrenomedullin, cortisol and ACTH can be considered part of a complex mosaic model of the neuroendocrine system during academic stress

Effect of alpha cypermethrin and/or selenium on plasma neurotransmitters in male albino rats

The present study was undertaken to investigate the role of selenium as an antioxidant on alpha-cypermethrin neurotoxicity in adult male albino rats. This was achieved by observing the changes occurring in the neurotransmitters in plasma. In this study, the animals were treated with 1/10 LD[50] of alpha-cypermethrin insecticide and/or selenium for 14 and 28 days. The data showed a significant increase in plasma norepinephrine [NE] and dopamine [DA] levels with a significant reduction in plasma serotonin [5-HT], 5-hydroxy indole acetic acid [5-HIAA] and acetylcholinesterase [AchE] were recorded. On the other hand, the level of plasma monoamine oxidase [MAO] showed a significant decrease after 14 days of treatment, then increased after 28 days. Combined supplementation of selenium [in drinking water] and alpha-cypermethrin [orally] exhibit the same changes in plasma neurotransmitters compared to alpha-cypermethrin alone. The results indicate that alpha-cypermethrin induced neurotoxicity is mediated by free radical and selenium didn't play a protective role against alpha-cypermethrin induced neurotoxicity

Neurohumoral activation in percutaneous coronary interventions: apropos of ten vasoactive substances during and immediately following coronary rotastenting.

BACKGROUND: Ischemia, left ventricular dysfunction, endothelial damage and hemodynamic changes during percutaneous coronary intervention can lead to neurohumoral activation. This may partly explain the frequent episodes of coronary spasm, hypotension and bradycardia which occur during the procedure. Rotastenting, by employing the two basic mechanisms for coronary interventions-debulking and dilatation-epitomizes percutaneous coronary interventions in general. We sought to investigate the neurohumoral changes during and immediately following coronary rotastenting. METHODS AND RESULTS: Eighteen patients undergoing elective rotablator atherectomy followed by balloon predilatation and stenting for chronic stable angina were studied. Four femoral vein blood samples were drawn from each patient at the start of the intervention (baseline), and 2 (postdebulking-2), 10 (postdebulking-10) and 60 (postdebulking-60) minutes. respectively, after the first complete passage of the rotablation burr across the whole length of lesion. Levels of 10 neurohormones, namely, endothelin-1, bradykinin, arginine vasopressin, norepinephrine, dopamine, epinephrine, angiotensin II, serum angiotensin-converting enzyme activity. atrial natriuretic peptide and kininogen were estimated in each sample. Endothelin-1 and bradykinin attained their peak levels in the postdebulking-2 samples. and the rise from 0.34+/-0.07 pmol/ml and 235.8+/-17.7 pg/ml to 0.42+/-0.06 pmol/ml and 337.2+/-41.0 pg/ml, respectively, was statistically significant (p<0.05). The level of arginine vasopressin showed a significant (p<0.05) rise from baseline (108.5+/-31.8 pg/ml) to postdebulking-60 samples (136.5+/-39.4 pg/ml). The other neurohormones did not show significant changes. CONCLUSIONS: The results suggest a definite but differential neurohumoral activation during and immediately following rotastenting. These neurohumoral changes may have a role in untoward intra- and postprocedural vasomotor and hemodynamic effects. This study establishes the concept of neurohumoral activation during percutaneous coronary interventions.

Actividad de la Indigofera suffruticosa Mill en la epilepsia crónica experimental y su relación con aminoácidos neurotransmisores / Activity of Indigofera suffruticosa Mill in experimental chronic epilepsy and its relation to neurotransmitter amino acids

Se determinaron los niveles de aminoácidos plasmáticos en el modelo de epilepsia experimental kindling inducido por lidocaína. Se ensayaron 5 grupos: un grupo de animales sin tratamiento, otro de animales kindleados, otro de animales kindleados al que se le suministró el menstruo y los 2 últimos grupos a los cuales se les adminitró por vía oral la dosis de 0.06 g/kg pc del extracto fluido de la planta Indigofera suffructicosa (añil cimarrón), en un grupo durante el tratamiento y en otro antes y durante el tratamiento en el desarrollo del modelo. Los niveles de aminoácidos, taurina, glicina, tirosina, fenilalanina, ácido glutámico y triptófano fueron cuantificados en un analizador de aminoácidos, y se encontró diferencias significativas (p < 0.05) en al ácido glutámico, taurina y glicina en los animales tratados con respecto a los controles. Se realizaron mediciones conductuales a lo largo de la experiencia