Blood flow oscillations at a frequency of about 0.1 Hz in skin microvessels do not reflect the sympathetic regulation of their tone

Wavelet analysis of blood flow oscillations recorded with laser Doppler flowmetry in finger glabrous skin microvessels was carried out in 82 subjects with different variations in the syndromes of hand and foot sympathectomy and denervation. As distinct from the 0.02–0.046-Hz (about 0.03–0.04 Hz) blood flow oscillations in skin microvessels of sympathetic thermoregulatory origin, no relationship was found between the presence of 0.07–0.015 Hz (about 0.1 Hz) vasomotions in the wavelet spectrum and intactness of sympathetic innervation in the tissue region. The use of the myogenic band oscillation parameters, in particular, the amplitudes of vasomotions, for assessing the state of sympathetic thermoregulatory innervation determining the neurogenic tone of skin microvessels is not physiologically correct. The influence of local environmental factors on the vasomotion parameters confirms their local origin. The local perfusion pressure value significantly influenced the amplitude but not the frequency of vasomotions. The amplitude dominance of vasomotions was observed upon a decrease in perfusion pressure, whereas a marked increase in perfusion pressure or venous congestion resulted in a sharp depression of their amplitudes. Under the sympathectomy conditions, the oscillatory dynamic component of the arteriolar myogenic tone in the glabrous skin of the extremity acral zones is involved in the blood flow’s autoregulation. The presence of fine sensory fibers is necessary to carry out the dynamic autoregulation of the blood flow. Sensory nonmyelinated fibers and the trophic neuropeptides secreted by them not only initiate independent oscillations in the low-frequency (0.047–0.069 Hz) myogenic band, but also contribute to the normalized amplitudes of vasomotions being increased. At the same time, no appreciable influence of the sympathetic vasomotor activity and the corresponding influence of catecholamines on the amplitude and frequency of vasomotions was observed.