ZIZYPHI FRUCTUS, A CONSTITUENT OF ANTIASTHMATIC HERBAL MEDICINE, STIMULATES AIRWAY EPITHELIAL CILIARY MOTILITY THROUGH NITRIC-OXIDE GENERATION

The effects of Zizyphi fructus, a major constituent of Chinese anti-as thmatic herbal medicine, on ciliary motility and nitric oxide (NO) gen eration in canine cultured tracheal epithelium were studied by the mic rophoto-oscillation method and the specific amperometric method, respe ctively. Addition of Zizyphi fructus at 100 mu g/mL rapidly increased ciliary beat frequency (CBF), an effect that was inhibited by N-G-nitr o-L-arginine methylester (L-NAME) but not by N-G-nitro-D-arginine meth ylester (D-NAME), and this inhibition was reversed by L-arginine but n ot by D-arginine. Immersion of the NO-selective electrode in the mediu m bathing tracheal epithelial cells showed a baseline current of 21.3- 60.4 pA, which corresponded to NO concentration ([NO]) at 34.4 +/- 7.8 nM. Zizyphi fructus caused a concentration-dependent increase in [NO] , the maximal increase from the baseline [NO] level and the concentrat ion of Zizyphi fructus required to produce a half-maximal effect (EC(5 0)) being 107 +/- 14 nM (p < .001) and 7.2 +/- 2.9 mu g/mL, respective ly. These results suggest that Zizyphi fructus enhances airway ciliary motility and that this effect is exerted through the stimulation of e pithelial NO generation.