title: [Effect of substance P on the potassium and calcium currents of colonic smooth muscle cells].
abstract: OBJECTIVE
  To investigate the effect of substance P(SP) on the spontaneous contractile activity of smooth muscle cells,the large-conductance calcium-activated potassium channel currents (IBKCa) and the L-type calcium channel currents (ICaL) in rat smooth muscle cells of the proximal colon.
  
  
  METHODS
  A total of 24 healthy male Wista rats were used in this test. The change of smooth muscle strips spontaneous contraction of rat proximal colon after adding SP was recorded by a physiological signal stystem (RM6240). The IBKCa and ICaL were measured via the whole cell patch-clamp technique.
  
  
  RESULTS
  The longitudinal muscle contraction was obviously increased concentration-dependently after adding different concentrations of SP (10(-7)-10(-6) mol/L), so as the circular muscle while adding SP(10(-8)-10(-6) mol/L) (all P<0.05). Compared with the control group, IBKCa was decreased after adding SP(10(-6) mol/L). Under the stimulating voltage of 60 mV, the IBKCa current density was (11.71±1.65) pA/pF, which was significantly lower compared with the control group (14.42±2.89) pA/pF (P<0.05). The ICaL) was apparently increased. Under the stimulating voltage of 0 mV, the ICaL) currents density was (-5.04±0.67) pA/pF, compared with the control group (-4.25±0.46) pA/pF, which was significantly increased (P<0.01).
  
  
  CONCLUSIONS
  SP can promote the spontaneous contractile activity of colon smooth muscle of rats in vitro.And SP decrease IBKCa representatively while apparently increase ICaL). That is probably one of the mechanism SP regulate the gastrointestinal motility.
authors.affiliation: Department of Gastroenterology, Renmin Hospital of Wuhan University, Key Laboratory of Hubei Province for Digestive System Diseases, Wuhan 430060, China.
authors.forename: Qincai
authors.initials: Q
authors.lastname: Tang
authors.affiliation: Department of Gastroenterology, Renmin Hospital of Wuhan University, Key Laboratory of Hubei Province for Digestive System Diseases, Wuhan 430060, China; Email: xhnk@163.com.
authors.forename: Hesheng
authors.initials: H
authors.lastname: Luo
authors.affiliation: Department of Gastroenterology, Renmin Hospital of Wuhan University, Key Laboratory of Hubei Province for Digestive System Diseases, Wuhan 430060, China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Quan
authors.affiliation: Department of Gastroenterology, Renmin Hospital of Wuhan University, Key Laboratory of Hubei Province for Digestive System Diseases, Wuhan 430060, China.
authors.forename: Han
authors.initials: H
authors.lastname: Fan
authors.affiliation: Department of Gastroenterology, Renmin Hospital of Wuhan University, Key Laboratory of Hubei Province for Digestive System Diseases, Wuhan 430060, China.
authors.forename: Guang
authors.initials: G
authors.lastname: Yu
mesh_terms: D000818:Animals; D002118:Calcium; D020746:Calcium Channels, L-Type; D003106:Colon; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008297:Male; D009119:Muscle Contraction; D009130:Muscle, Smooth; D018408:Patch-Clamp Techniques; D011188:Potassium; D051381:Rats; D013373:Substance P
chemical_list: D020746:Calcium Channels, L-Type; D051036:Large-Conductance Calcium-Activated Potassium Channels; D013373:Substance P; D011188:Potassium; D002118:Calcium