A New Means of Control of Action of Ciliated Epithelium. Effect of Moisture.

Abstract

It has been proved by the authors that ciliary movement, though initiated automatically, is regulated, like movement of other types of visceral contractile tissue of higher organisms (vertebrate), by sympathetic and parasympathetic nervous acceleration and inhibition, and by sympatho- and parasympatho-mimetic types of chemicals. We here present another factor of control of the rate of activity of this tissue, not described heretofore, namely, moisture. We have found during the last 2 years that the propulsive power of ciliated epithelium is absolutely dependent upon the presence of a surface film of fluid, since this power is completely paralyzed by drying. The method for determining ciliary speed rate was the same as that formerly reported. 1 The average time in seconds required for a fine, light particle upon the mucus membrane of the palate and pharynx of the frog to cross the field of a binocular microscope was recorded. The movement, or lack of movement, during and after various degrees of drying of the mucus membrane was recorded. Drying was done by blowing air gently from a rubber bulb upon the surface. We have also used mammals in similar experiments.

In every case evaporation of the surface film of moisture slowed and finally stopped completely its propulsive action, when drying was maintained. The particle remained at a stand-still upon the mucosa as long as the ciliated surface lacked a film of fluid. When moisture (physiological saline, Ringer's solution, or tap water) was again added after incomplete drying the ciliary propulsive action was resumed but at a slower rate. Ciliary activity was not resumed upon the addition of moisture after complete drying.

We also confirmed repeatedly the principle, noted by Kraft, 2 Gray, 3 and others, that the rate of ciliary activity is profoundly influenced by temperature, since on cold days one to several minutes was required for the particle to cross the microscopic field; whereas in hot weather its speed was rapid.