ABSTRACT
The present work was undertaken in order to investigate the noradrenergic system and skeletal muscle heat shock protein 72 (HSP72) response to static magnetic field (MF) in male rats. At thermoneutrality (25 degrees C), the exposition of rats 1 hour/day for 5 consecutive days to MF of 128 mT (m tesla) induced an increase in norepinephrine content in gastrocnemius muscle (+25%, p < 0.05) but had no effect at 67 mT (+1%, p > 0.05), indicating a stimulatory effect of sub-acute MF exposure on the noradrenergic system activity. Moreover, exposed rats to MF displayed a non-significant increase of HSP72 levels in gastrocnemius muscles (+29%, p > 0.05). The results indicate that noradrenergic systems in rat's gastrocnemius muscles are affected by MF exposure. Interestingly, sub-acute exposure insufficiency increased HSP72 levels in gastrocnemius muscles.
Subject(s)
Electromagnetic Fields/adverse effects , HSP72 Heat-Shock Proteins/radiation effects , Muscle, Skeletal/innervation , Muscle, Skeletal/radiation effects , Norepinephrine/radiation effects , Radiation , Sympathetic Fibers, Postganglionic/radiation effects , Animals , Blood Vessels/innervation , Blood Vessels/physiology , HSP72 Heat-Shock Proteins/metabolism , Male , Muscle, Skeletal/metabolism , Norepinephrine/metabolism , Rats , Rats, Wistar , Stress, Physiological/metabolism , Stress, Physiological/physiopathology , Sympathetic Fibers, Postganglionic/metabolism , Time Factors , Up-Regulation/physiology , Up-Regulation/radiation effectsABSTRACT
To evaluate the effect of bright light on the sympathetic nervous system in human, muscle sympathetic nerve activity (MSNA) was recorded from the peroneal nerve in five healthy subjects. Each subject was exposed to bright light of 5000 lx for 20 min. After the bright light exposure, MSNA became significantly enhanced. The heart rate increased transiently only during the bright light exposure. The blood pressure did not change significantly during and after the bright light exposure. The result is the first direct evidence showing that bright light modulates the activity of the sympathetic nervous system in normal human.
