Possible synergies between isatin, an endogenous MAO inhibitor, and antiparkinsonian agents on the dopamine release from striatum of freely moving rats.

Isatin is an endogenous indole that inhibits monoamine oxidase (MAO). When exogenously administered, it increases the striatal dopamine and acetylcholine levels and presents neuroprotective effects in the brain. Previous studies show that intrastriatal administration of isatin increased the in vivo dopamine release from striatum in a concentration-dependent form. In the present work, we investigated the effects of combined administration of isatin together with other substances actually used in antiparkinsonian pharmacotherapy on in vivo dopamine overflow. For this, we co-administered isatin with the MAO inhibitors selegiline and clorgyline, l-DOPA, the catechol-o-methyl-transferase (COMT) inhibitors tropolone and dinitrocatechol, with the dopaminergic agonist ropinirole, and with the psychostimulant caffeine, in order to evaluate possible synergies between these substances to increase the dopamine extracellular levels in freely moving rats. Intrastriatal administration of isatin (10 mM, 60 min) significantly increased dopamine release to 1164 ± 152%, compared to the baseline. Co-administration of isatin together with selegiline (1 mM) or clorgyline (1 mM) alone or in combinations showed a similar profile to increase in vivo dopamine release. Intrastriatal infusion of isatin together with antiparkinsonian drugs l-DOPA (25 µM), tropolone (1 mM), dinitrocatechol (100 µM), amantadine (5 mM) and caffeine (5 mM) significantly elevated extracellular dopamine levels more than any single drug, showing a good neurochemical synergy by improving the effect of isatin on the extracellular dopamine levels in the striatum. Infusion of isatin + ropinirole (5 mM) did not change the isatin-induced increase in dopamine overflow. These results could be useful to carry out further investigations with a possible clinical application.

El papel del ejercicio aeróbico en la prevención y manejo de la fibrilación auricular. ¿Amigo o enemigo? / The role of aerobic exercise in the prevention and management of auricular fibrillation. Friend or foe?

La fibrilación auricular es la arritmia que presenta mayor prevalencia en la población a nivel mundial. De hecho, la bibliografía científica existente parece mostrar también una elevada prevalencia en deportistas de resistencia. Sin embargo, actualmente la relación entre la fibrilación auricular y el ejercicio aeróbico resulta controvertida. Por un lado, el ejercicio aeróbico puede considerarse una herramienta de prevención primaria para el desarrollo de enfermedades cardiovasculares, incluidas las arritmias. Por otro, realizar actividades de alta intensidad de manera regular con grandes volúmenes, ha sido identificada por algunos autores como un factor de riesgo. Actualmente, se desconoce el mecanismo exacto por el cual el ejercicio aérobico podría incrementar el riesgo de fibrilación auricular, pero podría estar relacionado con cambios anatómicos y funcionales a nivel cardíaco. Esta revisión pretende realizar una actualización del efecto que presenta el ejercicio aérobico sobre la fibrilación auricular para establecer una pauta de prescripción. Los resultados del presente trabajo, según la evidencia actual, parecen mostrar al ejercicio aérobico como una estrategia no farmacológica útil tanto para la prevención, como para el tratamiento de la fibrilación auricular. El efecto preventivo del ejercicio aeróbico en la fibrilación auricular parece estar relacionado con la disminución de factores de riesgo asociados. Aunque no existe consenso sobre la carga de ejercicio, se considera que el ejer-cicio aeróbico debería practicarse regularmente y a una intensidad moderada-vigorosa para alcanzar los mayores beneficios. Se requieren más investigaciones para determinar los mejores parámetros de ejercicio aeróbico en la fibrilación auricular

Atrial fibrillation is the arrhythmia with the highest prevalence world-wide. In fact, scientific literature seems to show a high prevalence of atrial fibrillation in endurance athletes too. However, currently the relationship between atrial fibrillation and aerobic exercise is controversial. On the one hand, aerobic exercise could be defined as a useful tool to be used as primary prevention strategy for the development of cardiovascular diseases, including arrhythmias. On the other hand, some authors identify it as a risk factor, specifically if it is performed at high intensity with large regular volumes. But the exact mechanism by which aerobic exercise might increase the risk of atrial fibrillation is unknown, although it could be related to anatomical and functional changes at the cardiac level. This review aims to update the knowledge about the effect of aerobic exercise on atrial fibrillation to establish a prescription pattern. The results of the present work, according to the current evidence, show the aerobic exercise as a non-pharmacological strategy, both for the primary and secondary prevention of atrial fibri-llation. The preventive effect of aerobic exercise on atrial fibrillation seems to be related to the reduction of associated risks. Although there is no consensus on the exercise load, it is considered that aerobic exercise should be practiced often and at a moderate-vigorous intensity to get the greatest benefits. More research is required to determine the best parameters of aerobic exercise in atrial fibrillation