Resumen de Role of alpha- and beta-adrenoreceptors in rat monocyte/macrophage function at rest and acute exercise
Juliane da Silva Rossato, Mauricio Krause, Augustus Joli Martins Fernandes, João Roberto Fernandes, Isis Lenhard Seibt, Anderson Rech, Paulo Ivo Homem de Bittencourt Jr.
Previous studies from our laboratory have demonstrated that a single bout of moderate exercise stimulates macrophage function, increasing phagocytic capacity, and production of hydrogen peroxide and nitric oxide (NO?) through nuclear factor kappa B activation. In this work, we investigated the role of ?- and ?-adrenoreceptors on the function of monocyte/macrophages during rest and exercise. Adult male Wistar rats were i.p. administered (100 ?L/100 g) with specific adrenergic antagonists before an acute moderate exercise bout: prazosin (?1-specific antagonist 2 mg/kg), propranolol (unspecific ?1/?2 antagonist 10 mg/kg), double blockade (?1 and ?1/?2), or phosphate-buffered saline (control). Acute exercise consisted in a single swimming session of moderate intensity (5 % body weight overload on the chest) for 60 min. Control groups (rest) received the same antagonists and were killed 60 min after drug administration. Exercise increased phagocytic capacity (1.7-fold, p < 0.05), NO? production (5.24 fold, p < 0.001), and inducible nitric oxide synthase (NOS2) expression (by 58.1 %), thus suggesting macrophage activation. The ?-adrenoreceptor blockade did not change this behavior. In resting animals, ?1 antagonist, as well as the double (?1/?) blockade, however, further increased phagocytic capacity (by up to 261 %, p < 0.001), NO? production (by up to 328 %, p < 0.001), and the expressions of NOS2 (by 182 %, p < 0.001) and HSP70 (by 42.5 %, p < 0.01) suggesting a tonic inhibitory effect of ?1 stimulation on macrophage activation. In exercised animals, ?1-blockade showed similar enhancing effect on phagocytic indices and expressions of NOS and HSP70, particularly in double-blocked groups, although NO? production was found to be reduced in exercised animals submitted to both ?- and ?-blockade. Redox (glutathione) status and lipoperoxidation were evaluated in all test groups and approximately paralleled macrophage NO? production. We suggest the prevalence of a peripheral ?1-adrenoreceptor inhibitory tonus that limits macrophage responsiveness but operates differently after physical exercise.
