Alpha₂-Adrenoceptor Inhibition in Patients with Vibration White Fingers

Abstract

In healthy subjects the physiological vasoconstriction to local cooling has been linked to sympathetic adrenoceptors of the alpha₂-subtype. The present study was designed to determine if the vasoconstriction in response to local cooling in patients suffering from vibration white fingers can be diminished by alpha₂-adrenoceptor inhibition. Six men with vibration white fingers, verified in a cold provocation test, were examined. To study the effect of local skin cooling blood flow was measured with laser doppler technique on the dorsum of dig. II or III. The temperature of the laser doppler probe was regulated by Peltier elements. Temperature could be lowered from 30°C to 20°C within 30s. Measurements were performed before and after local inhibition of the alpha₂-adrenoceptors. This was achieved by the introduction of the selective alpha₂-adrenoceptor inhibitor, rauwolscine, into the finger skin by iontophoresis. During control conditions local cooling consistently resulted in a marked vasoconstriction. Inhibition of the alpha₂-adrenoceptors by rauwolscine completely abolished this effect. The present data indicate that substances inhibiting alpha₂-adrenoceptors may be of therapeutic value in patients with vibration white fingers.