ABSTRACT
Aim To investigate the effects of curcumol on the contractile activity of isolated duodenal smooth muscle in rats and explore its underlying mechanisms. Methods The isolated duodenum specimens of rats were made. The effects of different concentrations of curcumol on the contraction of isolated duodenal smooth muscle were observed using BL-420F biological and functional experimental system with constant tem-perature perfusion method. A certain concentration of curcumol was combined with atropine,isoproterenol, norepinephrine,calcium-free Krebs solution,verapam-il respectively to observe its effect on smooth muscle contraction. Results Curcumol could stimulate duo-denal smooth muscle in vitro,and increase its contrac-tile amplitude and tension significantly. It could be an-tagonized partly by atropine,isoprenaline,norepineph-rine,verapamil. Conclusion Curcumol can promote the contraction of isolated duodenal smooth muscle in rats,which may be achieved by stimulating M recep-tor,inhibiting α and β receptors,and promoting the extracellular calcium influx.
ABSTRACT
Aim To observe the influences of dexmen-detomidine on the spontaneous contraction of duodenal smooth muscle of rabbits in vitro and explore the mech-anisms.Methods The rabbits ( male or female ) were stunned and the duodenums were isolated .The sam-ples of duodenal segments were connected with tension transducer , which were then put into oxygen saturation Krebs-Henseleit ( K-H) solution .The influences of dex-mendetomidine on amplitude ( AM ) and frequency ( FR ) of duodenal smooth muscle were recorded by BL-420 F biological signal processing system .The cu-mulative dosing method was used to observe the differ-ent concentrations of dexmedetomidine on duodenal smooth muscle spontaneous contraction .Glibenclamide ( Gli) was added to K-H solution before dexmendeto-midine.In the calcium-free K-H solution, calcium chloride and rynodine were added before dexmendeto-midine.The mechanisms of dexmendetomidine were studied .Results ① Dexmendetomidine reduced the amplitude of spontaneous contraction of duodenal smooth muscle in rabbits in a dose-dependent manner ( P0.05 ) .② Gli ( P <0.05 ) partly abolished the inhibitory effects of dexmendetomi-dine on duodenal smooth muscle .③ Dexmendetomi-dine inhibited the contraction of duodenum smooth muscle induced by calcium chloride ( P <0.05 ) and rynodine ( P<0.05 ) application into calcium-free K-H solution.Conclusion Dexmendetomidine inhibits the spontaneous contraction of duodenal smooth muscle of rabbits in vitro.The mechanisms may be related to ac-tivating ATP sensitive potassium channels , inhibition of the extracellular calcium influx via cell membrane and intracellular calcium release via sarcoplasmic reticulum in duodenal smooth muscle .