The influence of the pH and osmotic pressure upon tracheal ciliary beat frequency as determined with a new photo-electric registration device.

A method for measurement of tracheal ciliary beat frequency in vitro is described. Light transmitted through the cilia is detected by a phototransistor mounted in a microscope, while the frequency is measured instantaneously and the waveform is displayed by an oscilloscope, connected to a transient recorder. Due to the magnification and the method of illumination, the movement of approximately 30 cilia is projected on the phototransistor. In Locke-Ringer solution the waveform shows a very constant amplitude. Interference arises after a noxious influence and is dependent on the frequency of the ciliary movement. The effect of pH and osmotic pressure on chicken embryo and rat tracheal ciliary beat frequency is assessed. The frequency is not influenced between pH = 7 and pH = 10, but higher and lower pH values decrease the frequency. Hypertonic NaCl solutions decrease the frequency of chicken embryo cilia as much as hypotonic NaCl solutions. Rat cilia turned out to be less sensitive for hypotonic NaCl solutions.