Abstract
When the function of salivary glands was abolished by applying ligatures to their ducts and the function of one half of the diaphragm muscle was abolished by sectioning of its phrenic nerve, the choline acetyltransferase activity was found to be increased in not duct-ligated glands and in the intact hemidiaphragm 4 weeks later. The increase was not seen within the first week. The increase in activity appears to be particularly manifested in the nerve endings, since it was seen in the hemidiaphragm but not in the phrenic nerve. Increased stream of impulses in the efferent nerves is thought to be the cause of this increase in choline acetyltransferase activity.