Analysis of the responses evoked in the cutaneous circulation of one hand by heating the contralateral hand.

In 9 healthy human subjects, cutaneous red cell flux in the thenor eminence of the left hand was measured by a Laser Doppler meter, while the right hand was transferred sequentially from water at 33 degrees C, to water at 42 degrees C for 5 min, to water at 33 degrees C (first experimental run) and then to water at 42 degrees C for 2 min (second experimental run). Red cell flux increased significantly by the end of the 2nd min of heating and had increased further by the end of the 5th min. Mean arterial pressure, measured by sphygmomanometry from the left arm, had not changed at either times indicating that the changes in red cell flux reflected progressive cutaneous vasodilation. Meanwhile heart rate was significantly increased by the 5th min. By contrast, when these experiments were carried out on 8 subjects with a cuff on the right arm inflated to approximately 60 mmHg to impede venous outflow from the heated limb, red cell flux in the contralateral hand showed a significant increase by the 5th min of heating, but this was accompanied by a fall in arterial pressure and no change in heart rate. By the 5th min after release of the occlusion and while the right arm was still in warm water, there was a further increase in red cell flux in the contralateral hand, but arterial pressure was not significantly different from the original control level and heart rate was significantly increased. Occlusion per se had no effect on red cell flux.(ABSTRACT TRUNCATED AT 250 WORDS)