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Involvement of sympathetic nerve activity in skin blood flow oscillations in humans

Research output: Contribution to journalJournal articlepeer-review

<mark>Journal publication date</mark>05/2003
<mark>Journal</mark>Anerican Journal of Physiology - Heart and Circulatory Physiology
Issue number5
Number of pages9
Pages (from-to)H1638-H1646
Publication StatusPublished
<mark>Original language</mark>English


We have used the wavelet transform to evaluate the time-frequency content of laser-Doppler flowmetry (LDF) signals measured simultaneously on the surfaces of free microvascular flaps deprived of sympathetic nerve activity (SNA), and on adjacent intact skin, in humans. It was thereby possible to determine the frequency interval within which SNA manifests itself in peripheral blood flow oscillations. The frequency interval from 0.0095 to 2 Hz was examined and was divided into five subintervals: I, similar to0.01 Hz; II, similar to0.04 Hz; III, similar to0.1 Hz; IV, similar to0.3 Hz; and V, similar to1 Hz. The average value of the LDF signal in the time domain as well as the mean amplitude and total power in the interval from 0.0095 to 2 Hz and amplitude and power within each of the five subintervals were significantly lower for signals measured on the free flap (P <0.002). The normalized spectral amplitude and power in the free flap were significantly lower in only two intervals: I, from 0.0095 to 0.021 Hz; and II, from 0.021 to 0.052 Hz (P <0.05); thus indicating that SNA is manifested in at least one of these frequency intervals. Because interval I has recently been shown to be the result of vascular endothelial activity, we conclude that we have identified SNA as influencing blood flow oscillations in normal tissues with repetition times of 20-50 s or frequencies of 0.02-0.05 Hz.