role of histaminegic and calcium channels in the inhibitory effects of hydroalcoholic extract of matricaria recutita l. on isolated rabbit jejunum

introduction: considering the long traditional history of anti-inflammatory and anti-spasmodic effects of matricria spices on the gastrointestinal system, the present study aimed to investigate the role of calcium channels and histamine receptors in the inhibitory effects of hydroalcoholic dry extract of german chamomile (matricaria recutita l.) on the isolated rabbit jejunum. methods: all experiments were done on the isolated jejunum of new zealand rabbits (1.8-2.5 kg). dry extract of aerial parts of m. recutita was obtained by the maceration technique. the study was performed on two groups (n=6 in each group). in the first group, the effects of cumulative concentrations of m. recutita (3×10-3-1×10-2 mg/ml) on normal and k+-induced contractions (50 mm) of isolated jejunum were studied. in the second group, the inhibitory role of m. recutita ( 3 – 13×10-3 mg/ml) was evaluated in the presence and absence of histamine and cetrizine. in the presence and absence of 10 μm certizine, a histamine h1-antagonist, a concentration-dependent inhibitory effect of m. recutita extract in the range of 3-13×10-3 mg/ml was recorded the rabbit jejunum. results: results showed that ec50 of m. recutita in the absence and presence of k+ was 6.3×10-3 and 6.5×10- 3mg/ml, respectively. ic50 values for two concentrations of m. recutita (8×10-3 , 1×10-2 ) to abrogated contractive phase of histamine was 9.55 × 10-6 and 1.57 × 10-6 μm. cetrizine (10 μm) abolished inhibitory effects of m. recutita (ic50=3.6×10-3), (p< 0.001). conclusion: dry extract of matricaria recutita had inhibitory effects on the contractions of isolated rabbit jejunum. calcium channels and histamine were involved in these antispasmodic effects.