[Influence of biophysical factors on redox processes and biological oxidation. 20. Tissue temperatures under...

The temperature differences obtaining in the subcutaneous tissues directly below the zone exposed to ultrasonic irradiation, the liver an the myocardium of white rats were measured during and after ultrasonic treatment. The only rise in temperature was observed in the tissues located below the field of ultrasonic irradiation after the second minute. The temperature drop in each of the three types of tissue examined is a characteristic feature. This paradoxical effect produced by ultrasonic intensities of 0.2, 0.6, 1.0, and 1.6 watt/cm-2, which has not as yet been described in the literature, may be explained by the control mechanisms keeping the internal body temperature relatively constant and, in particular, by those mechanisms of temperature regulation which are controlled by the biogenic amines.