The purpose of this study was to investigate the iontophoretic effect of epinephrine on
the compound muscle action potential (CMAP) and physiological aspects of nerves and
muscle, to increase the function of physical therapy. Twenty healthy men ranging 20-30
years were divided in two groups (iontophorsis and direct current). Epinephrine solution
(1 mg/ml) was used for iontophoresis and normal saline for direct current. After
recording CMAP, iontophoresis and direct current were applied for each group.(50 mA.
min) by placing an active electrode on CMAPs were examined at 1, 5, 10 and 15
minutes after the iontophoresis and direct current stimulation and then compared with
an average of 5 recordings before application of iontophpresis and direct current.
The results of this study show that iontophoresis of epinephrine increases after
amplitude 5, 10, and 15 minutes (p<0.05) and increases positive peak, duration and
rising time after 1,5,10, and 15 minutes (p<0.05). Increased repolarization in the first
minute after iontophoresis was significant (P<0.05). Direct current increases the
duration, rising time, propagation of depolarization and repolarization time at 1, 5, 10
and 15 minutes (P<0.05). The slope of propagation after iotophoresis increase at 10
minutes (P<0.05) where as direct current reduces the slopes of rising, propagation, and
repolarization of CMAPs at 1,5,10 and 15 minutes (P<0.05). These findings indicate
that iontophoresis of epinephrine effect the neuromuscular junction to increase muscle
fibers involvement where as direct current stimulation with hyperpolarization reduce
suitable activities of muscle fibers.