EFFECT OF ATRIAL-NATRIURETIC-FACTOR ON SKIN MICROCIRCULATION VERSUS SKELETAL-MUSCLE BLOOD-FLOW

The response of the skin microcirculation and of forearm skeletal musc le blood flow to infusion of alpha-human (99-126) atrial natriuretic f actor (ANF) into the brachial artery was investigated in 15 young (18- 25 years) healthy volunteers in a double-blind, randomized, placebo-co ntrolled study. The forearm blood flow (FBF) was measured with venous occlusion plethysmography, and the skin flux was measured by using las er Doppler fluxmetry (LDF). Dose-response curves were made using incre asing dosages of ANF: 1, 10, and 100 ng/min/dl forearm volume. The FBF showed a significant, dose-dependent increase during ANF infusion, av eraging 107 +22% during the highest ANF dosage, as compared with -5 +/ - 9% during placebo (p < 0.001). For the LDF, these numbers were 34 +/ - 21 and 16 +/- 10%, respectively (NS). In two subgroups of subjects, the effect of ANF on microvascular reactivity was assessed by register ing the vasoconstrictor response to cold exposure (n = 7) and the vaso dilator response to arterial occlusion (n = 7). ANF did not change the microvascular response to these stimuli. ANF induces a dose-dependent increase in skeletal muscle BF without a relevant response in the ski n microcirculation. ANF does not play an important role in the regulat ion of skin perfusion.