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

There are many analogies between cold-induced vasodilatation (CIV) and vaso motion (VM), but the demonstration of any relationship between these two mi crovascular homeostatic reactions is to date lacking. In a group of seven c ontrols and seven patients with Raynaud phenomenon in the vasomotor stage o f the disease, we studied, by means of laser Doppler fluxmetry, the fingert ip flow at room temperature (15 min), during hand immersion into cold water (0-6 degrees C, 30 min), and at room temperature again (15 min). The Fouri er spectral analysis of the laser Doppler signal revealed in both groups tw o different patterns of the fingertip flow oscillations: the first was char acterized by continued oscillations with small amplitude and median frequen cy of 2-8 cycles/min occurring both at room temperature and during cold sti mulation. The second was characterized by continued oscillations of high am plitude and median frequency of 1 cycle/4-6 min occurring during cold stimu lation only. The first pattern of flow oscillations still occurred during t he second. The high-frequency oscillations are similar to the waves of vaso motion 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 no w oscillations may be an expression of the AVA's VM. (C) 1999 Academic Pres s.