Use of ultrasound to control ion transport via changes in membrane bound ATPase activity

Ultrasound frequencies ranging from 26 kHz to 10 MHz are used in a number of applications varying from cell disruptions to therapeutic and diagnostic procedures. Previous results demonstrated that 1 MHz ultrasound at therapeutic intensities causes significant changes in the electrophysiological properties of epithelial tissues. The nature of these alterations indicated that, among other effects, the Na/K-dependent ATPase activity of the tissue was reduced. This study examined if ultrasonic irradiation does effect ATPase activity. Two model systems were studied, a “free” solution of ATPase and a membrane-incorporated Na/K-dependent ATPase. The experiments indicated an irreversible decreased in enzyme activity for both systems and that sono-chemical (e.g., free radicals) and not thermal effects are responsible. These results support the authors´ hypothesis from previous electrophysiological observations on frog skin preparations that the effects of ultrasonic irradiation were, in part, due to effects on the activity of Na/K-dependent ATPase. Furthermore, the results of this study demonstrate that sono-chemical-induced enzyme activity changes may represent a much more common and pervasive effect than is commonly realized