EFFECT OF EXOGENOUS ATP AND PHYSICAL STIMULATION ON CILIARY FUNCTION IMPAIRED BY BACTERIAL-ENDOTOXIN

The effects of exogenous ATP and physical stimulation on ciliary beat depressed by lipopolysaccharide from Pseudomonas aeruginosa were studi ed in cell culture. Both the ciliary beat frequency (CBF) and the ampl itude (CBA) of human respiratory cells in monolayer cell cultures were studied by using a differential interference microscope equipped with a high speed video. Both the ATP and the physical stimulation stimula ted temporarily the depressed CBF and CBA. In both groups the CBF and CBA increased in 1 min to the initial level and then gradually decreas ed to the level before the stimulation. The duration of the ATP stimul ation on the CBF (10.1 +/- 1.8 min) and CBA (10.1 +/- 2.3 min) were si gnificantly better than the duration of physical stimulation on CBF (8 .0 +/- 1.8 min) and CBA (6.8 +/- 1.6 min). However, the areas under th e CBF/CBA curves (from the beginning of stimulation until the initial lever of CBF or CBA was reached again) did not differ significantly. A fter the removal of the bacterial toxin the CBF was restored to the in itial level. In the present study the adenosine receptor antagonist co uld not prevent the ciliostimulative effect of exogenous ATP combined with the physical stimulation. Both exogenous ATP and physical stimula tion have a clear but temporary stimulative effect on the ciliary beat depressed by bacterial toxin, ATP being slightly more effective. It s eems that the effects of ATP are not mediated by adenosine receptors.