title: [Regulation of vascular tension in diabetic coronary artery by large conductance Ca(2+)-activated K(+) channel in rats].
abstract: OBJECTIVE
  to investigate the regulation in vascular tension of diabetic coronary artery by large conductance Ca(2+)-activated K(+) channel (BK channel) and to elucidate the mechanisms of coronary dysfunctions due to diabetes.
  
  
  METHODS
  regulation of vascular tension in normal coronary artery was evaluated by videomicroscopy system. Streptozotocin-induced rat diabetic animal model was established successfully by intraperitoneal injection. Coronary smooth muscle cells were isolated by enzyme digestion. The BK currents in control and diabetic groups were recorded by patch clamp technique in whole cell configuration. Changes of vascular tension in normal and diabetic coronary arteries were assayed by multi-wire myograph system.
  
  
  RESULTS
  more than 50% was contracted in inner diameters of coronary arteries when 100 nmol/L IBTX, a specific BK channel blocker, was applied. In comparison with normal group, the BK current densities in diabetic group significantly decreased when test potentials were more than 60 mV (P < 0.05). The BK current densities at 150 mV in normal group and diabetic group were (275 ± 40) pA/pF and (70 ± 10) pA/pF respectively. When 100 mmol/L KCl was washed out, vascular tensions of normal and diabetic coronary artery were (398 ± 38) mg and (390 ± 35) mg respectively (P > 0.05); however, when 100 nmol/L IBTX was added, the vascular tensions of normal and diabetic coronary artery were (395 ± 40) mg and (50 ± 7) mg (P < 0.05).
  
  
  CONCLUSIONS
  BK channels play an important role in the regulation of coronary vascular tension, whereas BK channels in diabetic coronary artery are dysfunction, BK currents decrease and vascular tensions increase.
authors.affiliation: Department of Cardiology, Affiliated People's Hospital of Nanjing Medical University, Wuxi Municipal People's Hospital, Wuxi 214023, China.
authors.forename: Ru-xing
authors.initials: RX
authors.lastname: WANG
authors.forename: Xiao-rong
authors.initials: XR
authors.lastname: LI
authors.forename: Zhen-yu
authors.initials: ZY
authors.lastname: YANG
authors.forename: Ku-lin
authors.initials: KL
authors.lastname: LI
authors.forename: Jie
authors.initials: J
authors.lastname: ZHENG
authors.forename: Chang-ying
authors.initials: CY
authors.lastname: ZHANG
authors.forename: Su-xia
authors.initials: SX
authors.lastname: GUO
authors.forename: Li-ping
authors.initials: LP
authors.lastname: SUN
authors.forename: Tong
authors.initials: T
authors.lastname: LU
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000378:metabolism* / Q000503:physiopathology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000503:physiopathology; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism*; D008297:Male; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D051036:Large-Conductance Calcium-Activated Potassium Channels