The sympathetic hazards of airborne ultrasound on ultrasound sensitive mice.
A commercially available ultrasonic equipment (55-50 kHz/sec, 425 W) operated at a distance of 4 m air space caused death in some mice. The physical energy propagated was quite small, being calculated at less than 0.21 W/cm2. Among many strains of mice, the RIII strain was especially sensitive to ultrasound, and the peak of sensitivity was at 3 to 4 weeks of age at which the mortality rate was 95/149 (64%). No death occurred when mice were pretreated by (a) removing all body hair, (b) by administration of morphine hydrochloridum with a tail reaction, and (c) administration of a sympathetic blocking agent. From these results it is assumed that the ultrasound energy absorbed by the body fur reaches the hypothalamus through the sensory nerves of the hair roots. After the hypothalamus where central sympathetic nerve functions are localized, the stimulus passes down the descending tract of the sympathetic nerve, reaching the cardiac nerves via the autonomic nerve ganglion. Thus, death could occur by shock of the sympathetic nerve reflex.
D000388:Air; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D003643:Death; D051379:Mice; D008815:Mice, Inbred Strains; D009020:Morphine / Q000494:pharmacology; D013045:Species Specificity; D014465:Ultrasonics / Q000009:adverse effects*
D009020:Morphine; D001285:Atropine