Conflicting effects of noradrenaline on ciliary movement of frog palatine mucosa.

The effects of noradrenaline on ciliary movement of frog palatine mucosa were investigated using the particle transport method. Prostaglandins and cyclic AMP concentrations in the mucosa were determined by radioimmunoassay. Concentrations of noradrenaline below 10(-7) M suppressed ciliary movement by about 40% as compared to the control level. The changeover from inhibition to acceleration of ciliary movement occurred at 10(-7) M noradrenaline. Ciliary movement was markedly accelerated by concentrations of noradrenaline over 2 X 10(-6) M. This acceleration was eliminated in the presence of inhibitors of prostaglandin biosynthesis such as indomethacin (14 microM) and aspirin (25 microM). The acceleration was not eliminated by an inhibitor of thromboxane A2 biosynthesis (OKY-1555). On the other hand, E type prostaglandin release was increased about 8 fold of control by treatment with 5 X 10(-5) M noradrenaline, while F type prostaglandin release was not affected by the treatment with 5 X 10(-5) M noradrenaline. Ciliary movement was markedly accelerated when prostaglandin E1 was administered. The concentration of cyclic AMP was increased about 2.1 fold by treatment with 5 X 10(-5) M noradrenaline. The possible mechanism of the effects of noradrenaline on ciliary movement is discussed in the light of these results.