Abstract
Application of ultrasound changes skin permeability. The change of skin permeability is affected by nonthermal actions and thermal actions. However, the studies about nonthermal actions have not been reported sufficiently. In the present study, we examined whether nonthermal effects of ultrasound would enhance water molecules transport through the excised frog abdominal skin. Ten frogs' skins were used for this experiment. The skin internal surface was exposed to 1MHz continuous ultrasonic vibration at the intensity of 0.5W/cm2 with a 10.7cm2 transducer of 3.7cm in diameter for 10min. Since application of ultrasound generates heat, a heat-only application was devised using the frog Ringer's solution heated to the same level of temperature as that after application of ultrasound to investigate the effect on molecules transport. Application of ultrasound produced a significant increase in transdermal transport of water molecules, and a heat-only application produced a significant decrease. These results were opposite to each other, suggesting that the nonthermal effects of ultrasound were responsible for enhanced water molecules through the skin.
