effect of hydroalcoholic extract of pycnocycla spinosa on rat isolated bladder contraction

hydroalcoholic extract of pycnocycla spinosa is a relaxant of rat ileum and inhibits diarrhea in mice. as p. spinosa extract has spasmolytic activity on ileum, it could also affect other smooth muscles like bladder. therefore, the aim of this study was to determine the effect of p. spinosa extract on rat bladder contraction. in an in vitro study, the effects of p. spinosa extract, nifedipine and propantheline were tested on isolated rat bladder contractions induced by acetylcholine (ach, 10  m) and kcl (80 mm). p. spinosa extract, concentration-dependently, inhibited the bladder contractions induced by ach with an ic50 of 265±28 mg/ml, and kcl with an ic50 of 518±86 mg/ml. the muscarinic cholinoceptor antagonist, propantheline, inhibited the response of ach without affecting kcl response. nifedipine, on the other hand, abolished the kcl response, while partially inhibiting the ach contraction in rat bladder. the antispasmodic effect of p. spinosa extract on bladder was observed at higher concentrations as compared to that of ileum. therefore, it is unlikely that p. spinosa extract at anti-diarrheal doses affect the normal bladder emptying function.