The effect of acoustic cavitation on the contraction force and membrane potential of rat papillary muscle.

In experiments on isolated rat papillary muscles an acoustic cavitation induced by continuous wave focused ultrasound (543 kHz with intensity up to 3 W/cm2) was found to result in reversible membrane depolarization by 54.0 +/- 1.4 mV (n = 5), loss of excitability and rise in resting tension up to 53.1 +/- 4.3% (n = 15) of contractile response in the control. It was supposed that the rapid recovery of excitability (69.3 +/- 10.3 s, n = 15) might be a result of Ca2+ pump activation and/or alterations of intercellular coupling when cavitation ends.