Figure 2: The electric circuit used for iontophoresis. 2 mA of direct current was applied for 5 min. (a) An ammeter was used to measure the amount of current flowing between the quantitative sudomotor axon reflex test capsule (anode) and a flexible plate electrode (cathode). (b) The capsule is attached to the anterior side of the thickest part of the forearm. The side of the capsule where it touches the arm is divided into concentric compartments, with 10% acetylcholine solution in the outside one. (c) The flexible plate is also attached on the anterior aspect, 10 cm distal to the capsule.