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Inhibition of human muscle sympathetic activity by sensory stimulation
Author(s) -
Donadio Vincenzo,
Kallio Mika,
Karlsson Tomas,
Nordin Magnus,
Wallin B. Gunnar
Publication year - 2002
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2002.019596
Subject(s) - stimulation , sensory system , sensory stimulation therapy , neuroscience , medicine , psychology
Surprising sensory stimuli causing arousal are known to evoke short‐lasting activation of human sympathetic activity in skin but not in muscle nerves; anecdotal observations suggest that there may even be an inhibition of muscle sympathetic nerve activity (MSNA). To test this hypothesis we recorded multiunit MSNA in the peroneal nerve in 19 subjects aged 19–71 years, while sensory stimuli, consisting of either an electrical skin stimulus to a finger or a visual flash, were delivered repeatedly with intervals of approximately 20 s. The stimuli were given either 200 or 400 ms after the R wave of the electrocardiogram. Dummy stimuli, consisting of trigger pulses without sensory stimulation served as controls. Electrical skin resistance reductions were monitored from the palm of a hand as electrodermal signs of arousal‐induced cutaneous sympathetic activity. On a group basis both types of sensory stimuli attenuated the amplitude of one or two bursts of MSNA, while no such effects occurred after dummy stimuli. Individually, the inhibition was evoked by at least one stimulus modality or delay in 16 subjects whereas in three subjects no significant inhibition occurred. Skin resistance responses were evoked in all subjects. Some subjects responded to one, others to both stimulus modalities, and electrical stimuli were more effective than visual stimuli in causing MSNA inhibition as well as skin resistance reduction. On the other hand, electrodermal signs of arousal were equally common in subjects with and without inhibitory responses. We suggest that the MSNA inhibition evoked by sensory stimuli is an arousal effect which varies markedly between individuals.