Inhibitory effects of Cistus populifolius on contractile responses in the isolated rat duodenum.

The medicinal plant Cistus populifolius L., shows an important dose-dependent spasmolytic activity. The ability of the Cistus extract to inhibit both acetylcholine (ACh) (3.4 x 10(-8)-6.8 x 10(-5) M) and CaCl2 (2 x 10(-4)-1.28 x 10(-2) M)-induced contractions and the relaxing effect on K+ (75 mM)-induced contractions may indicate a non-specific receptor antagonist. However, this action may be related to the influx of extracellular Ca2+. These antispasmodic effects are partly consistent with the use of C. populifolius in folk medicine for certain gastrointestinal disorders.