Onset of exercise increases lumbar sympathetic nerve activity in rats

摘要: We hypothesized that lumbar sympathetic nerve activity (LSNA) increases at the onset of whole-body dynamic exercise in rat. To test this hypothesis, we recorded LSNA, heart rate (HR), and arterial pressure (AP) rest during a graded six adult rats. Rats were instrumented with venous catheters recording electrodes around trunk. Following recovery, each rat ran continuously on hand-driven or motorized treadmill 6 m.min -1 , 12 18 10% grade for approximately 3 min workload. Before exercise, mean (MAP), HR, LSNA averaged 108 ± 4 mm Hg, 385 20 bpm, 100%, respectively. As hypothesized, all variables increased abruptly dramatically exercise. For example, MAP (117 5 Hg), HR (450 15 bpm), (225 19%) significantly within first 25 s running . continued, there was progressive increase ; however, plateaued m.mi Since rat, suggest is mediated by central (feed forward) mechanism.