DRUG EFFECTS ON ELECTRICAL-ACTIVITIES OF THE CANINE TRACHEAL CILIATED CELLS

Effects of drugs on the tracheal ciliated cell of dogs were studied with reference to relationship between intracellular electrical activity and ciliary movement. The mucosal specimen of tracheal membranous wall of animals was mounted in a chamber containing Hanks solution at 36° The bioelectrical activity was recorded by the microelectrode method, and the changes in ciliary motility was estimated by measuring the mucus transport rate. At a depth of 5—25 μ from the mucous surface, a negative potential of a magnitude of -28.6±1.1 mV, was obtained. This resting potential had oscillating potential changes, with the amplitude of 200.4±20.9 μV, and the frequency of 13.8±1.2 Hz. Elevated K ion of the external medium of up to 40 mM caused a slight membrane depolarization without accompanying any spike potential. The depolarization appeared with increases in amplitude and frequency of the oscillatory potential and in ciliary motility, while a stronger depolarization over 15 mV with 60—120 mM K ion decreased the amplitude, frequency and motility. Acetylcholine and adrenaline (10-6-10-2 M) caused a cilioexcitation, and increased amplitude and frequency of the oscillatory potential. On the other hand, 5-hydroxytryptamine, dibucaine and lidocaine caused both cilioinhibition and decreases in amplitude and frequency. These findings suggest that the oscillations are the electrical activity which is closely related to the mechanical activity in the beating cells; the amplitude of oscillatory potential is probably correlating to ciliary beating force and the frequency correlating to beat frequency. Intracellular electrical activities of the ciliated cell are, thus, useful indices for elucidating properties of ciliated cells and in studying a mechanism of drug action on ciliary motility. © 1979, The Pharmaceutical Society of Japan. All rights reserved.