A model for investigating the effect of drugs on the peripheral sympathetic nervous system in man.

A model for assessing the effect of sympatholytic drugs on the peripheral sympathetic nervous system in man is described. Guanethidine, a sympatholytic drug, and the vehicle have been used to explore the model which is based on the Bier block. Sympathetic activity was assessed by measuring: (i) palmar sweating; (ii) skin temperature; (iii) radial/brachial pressure index; (iv) hand blood flow; and (v) vasoconstrictor ice response of hand blood flow. Neither the tourniquet nor the vehicle had any effect on sympathetic activity whereas guanethidine produced significant changes in skin temperature (P less than 0.05), hand blood flow (P less than 0.001) and the vasoconstrictor ice response (P less than 0.002), illustrating the usefulness of the model.