Effect of Hydroalcoholic Extract of Pycnocycla spinosa on Rat Isolated Bladder Contraction

Abstract

Introduction Pycnocycla spinosa Decne. Ex Boiss. var. spinosa (Fam. Umbelliferae) is a wild plant, growing in Iran (1, 2). Hydroalcoholic extract of P. spinosa is a potent relaxant of isolated ileum (3). In addition, P. spinosa extract was shown to have anti-diarrheal action at doses of 250 mg/kg to 1 mg/kg in mice (3). The anti-spasmodic action of P. spinosa extract is very similar to that of dicyclomine (4) and its anti-diarrheal dose on castor oil-induced diarrhea is very close to that of loperamide (5) and diphenoxylate (6). Therefore, P. spinosa extract could be an alternative remedy for the treatment of gastrointestinal spasm and diarrhea. The underlying mechanism of anti-diarrheal action of P. spinosa extract is most likely related to its gut motility inhibition. It has been shown that P. spinosa extract inhibits ileum contraction induced by KCl, acetylcholine (ACh) and serotonin (3) and therefore, P. spinosa extract may have an inhibitory effect on other smooth muscles, including bladder. Thus, the objective of this study was to investigate the effect of P. spinosa extract on rat isolated bladder contractions for the purpose of comparison with the ileum. Experimental Plant material Aerial parts of P. spinosa were collected and prepared as described before Abstract 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