Is there any relationship between cold-induced vasodilatation and vasomotion?

There are many analogies between cold-induced vasodilatation (CIV) and vasomotion (VM), but the demonstration of any relationship between these two microvascular homeostatic reactions is to date lacking. In a group of seven controls and seven patients with Raynaud phenomenon in the vasomotor stage of the disease, we studied, by means of laser Doppler fluxmetry, the fingertip flow at room temperature (15 min), during hand immersion into cold water (0-6 degreesC, 30 min), and at room temperature again (15 min). The Fourier spectral analysis of the laser Doppler signal revealed in both groups two different patterns of the fingertip flow oscillations: the first was characterized by continued oscillations with small amplitude and median frequency of 2-8 cycles/min occurring both at room temperature and during cold stimulation. The second was characterized by continued oscillations of high amplitude and median frequency of 1 cycle/4-6 min occurring during cold stimulation only. The first pattern of flow oscillations still occurred during the second. The high-frequency oscillations are similar to the waves of vasomotion and the low-frequency oscillations are similar to the waves of cold-induced vasodilatation. Because 90-98% of the fingertip flow passes through arteriolar-venular anastomosis (AVAs), our results suggest that the CIV flow oscillations may be an expression of the AVA's VM.