Sympathetic nerve activity during prolonged rhythmic forearm exercise

摘要: Exercise is a potent stimulus to activate the sympathetic nervous system. Previous work suggests that metabolite-sensitive muscle afferents are activated near point of fatigue, and, when activated, they determine nerve activity (MSNA) response isometric forearm exercise. Yet, studies using more prolonged rhythmic exercise paradigm suggest system can be in graded fashion. The purpose this study was whether metaboreceptor stimulation would also responsible for MSNA responses isotonic Subjects (n = 16) performed at 25% maximal voluntary contraction 30 min as we measured (microneurography). We observed progressive increases with peak increase 161 units from baseline value 180 units. posthandgrip circulatory arrest (PHG-CA) nine these subjects. This maneuver isolates contribution MSNA. During PHG-CA, delta values were not different those during freely perfused recovery period 7). compared seen static protocol 40% five two types caused similar MSNA, but only associated sustained PHG-CA. Finally, 31P-nuclear magnetic resonance used evaluate metabolic and 6). Static acidosis an H2PO4-, whereas had no effect on metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)