title: [The effect of emodin on the contraction of isolated jejunum smooth muscle of rats].
abstract: OBJECTIVE
  To investigate the effect of emodin on the contraction of jejunum smooth muscle and its underlying mechanisms.
  
  
  METHODS
  Rats were randomly divided into 7 groups (n = 6): control group, emodin group (1, 5, 10, 20 micromol/L), propranolol (PRO) plus emodin group, glibenclamide (GLI) plus emodin group, NG-Nitro-L-arginine Methyl Ester (L-NAME) plus emodin group, calcium free control group and calcium free emodin group. The rats were sacrificed by cervical dislocation and the small intestine was isolated. The jejunum segment specimens were mounted on an Organ Bath System with a tension transducer. The effect of emodin on contraction of jejunum smooth muscle was measured by BL-420E+ biological signal processing system and the amplitude (AM), tension (TE) and frequency (FR) of contraction were determined.
  
  
  RESULTS
  (1) Emodin inhibited the tension and amplitude of jejunum smooth muscle contraction in a dose-dependent manner (P < 0.05, P < 0.01) while the frequency was not obviously influenced. (2) PRO (P < 0.05) or GLI (P < 0.01) partly abolished the inhibitory effect of emodin on jejunum smooth muscle. (3) L-NAME had no obvious effect on the inhibitory effect of emodin. (4) Emodin attenuated the contraction of jejunum smooth muscle induced by calcium chloride application into calcium free K-H solution (P < 0.01).
  
  
  CONCLUSIONS
  Emodin obviously inhibits the amplitude and tension, while has no influence on the frequency of jejunum smooth muscle contraction in rats. Activation of beta adrenergic receptor, open of ATP sensitive potassium channels, and inhibition of the extracellular calcium influx through calcium channels of smooth muscle cell membrane might be involved in the process.
authors.forename: Pan
authors.initials: P
authors.lastname: Hu
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Liu
authors.initials: L
authors.lastname: Gao
authors.forename: Xiao
authors.initials: X
authors.lastname: Han
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Jiang
authors.forename: Hui-Jie
authors.initials: HJ
authors.lastname: Ma
authors.forename: Zan
authors.initials: Z
authors.lastname: Guo
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D020013:Calcium Signaling; D004642:Emodin / Q000494:pharmacology*; D005905:Glyburide / Q000494:pharmacology; D007583:Jejunum / Q000187:drug effects*; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats
chemical_list: D011433:Propranolol; D004642:Emodin; D005905:Glyburide; D019331:NG-Nitroarginine Methyl Ester