Ultrasonic effects on mammalian intestinal muscle membrane

The effects of ultrasound on the bioelectric activities of rat intestinal muscle were studied. It was found that low level ultrasound of 1.5 W/cm2 inhibited action potentials of the intestinal smooth muscle. This biophysical action of ultrasound had accumulative effects. The presence of high Ca++ in the medium (3.4 mM or 2 x normal [Ca++]) prevented this action of ultrasound. These data suggested that ultrasound probably acted on the calcium influx mechanism of the cell membrane.