Abstract
The respiratory reaction produced by sulfur dioxide was studied with the dd strain mice. Sensory irritation by sulfur dioxide was accompanied with a rapid decrease in respiratory rate which reached a peak within a few minutes and was followed by a gradual recovery while exposure continued.
The degree of maximum response was directly proportional to the exposure concentration. Xylocain aerosol did not change the respiratory response to sulfur dioxide, indicating that the receptor sensitive to sulfur dioxide can not be affected by local anesthesia. The mice desensitized by a given concentration of SO2 to its sensory irritation still reacted to another higher concentration of SO2 in a fashion less sensitive than the normal mice not previously exposed to SO2. The rate of desensitization was dependent on time rather than on concentration of SO2, but it seems that there is a certain limit in the magnitude of desensitization which depends on the concentration of SO2.
