Suaeda asparagoides (Miq.) has long been used as a Korean folk herbal medicine for the treatment of functional gastrointestinal disorders. However, reports on its pharmacological activity on gastrointestinal motility are scarce. The present study investigated the effects of Suaeda asparagoides water fraction of the extract (SAWF) on antral motility in vitro. Muscle strips from rat gastric antrum were set up in an organ bath in a circular orientation. SAWF (100 µg/mL) inhibited the spontaneous contraction of antral circular muscle strips. These inhibitory effects were not significantly affected by tetrodotoxin (1 µM), N(ω)-Nitro-L-arginine methyl ester hydrochloride (100 µM), 1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one (10 µM), ryanodine (10 µM) and phentolamine (10 µM). SAWF-induced inhibition was mostly restored by cyclopiazonic acid (10 µM). Furthermore, the β-adrenergic receptor antagonist, propranolol (10 µM), abolished SAWF-induced inhibition. These results suggest that SAWF may exert its activity on gastrointestinal smooth muscle via â-adrenergic receptors and sarcoplasmic reticulum Ca(2+) ATPase.
Keywords: SERCA; Suaeda asparagoides; gastric antrum; spontaneous contraction; β-adrenoceptor.