title: [Comparison of pharmacological characteristics of the endothelial target for acetylcholine between big artery and small artery].
abstract: OBJECTIVE
  To compare the differences of pharmacological characteristics of the endothelial target for acetylcholine (ETA) between rat aorta and tail artery.
  
  
  METHODS
  Differences in the endothelium-dependent relaxation induced by acetylcholine (ACh: 10(-8) - 10(-4) mol/L) were studied using isolated rat tail artery helical strips and aortic rings, so that the pharmacological characteristics of ETA in small artery can be observed.
  
  
  RESULTS
  ACh-induced endothelium-dependent relaxation was observed both in rat tail artery strips and in aortic rings precontracted with potassium chloride (60 mmol/L) in a concentration-dependent manner. In tail artery this effect was partially blocked by L-N(omega)-Nitro-arginine methyl ester (L-NAME: 10(-4) mol/L) or methylene blue (MB: 10(-5) mol/L), together with indomethacin (Indo: 10(-4) mol/L), but in aorta it was completely blocked by L-NAME or MB.
  
  
  CONCLUSIONS
  It is different of the pharmacological characteristics of ETA between big artery and small artery. A non-NO and non-PGI2 relaxing factor, together with nitric oxide (NO) and prostacyclin (PGI2), mediates endothelium-dependent vasorelaxation induced by ACh in small artery, but NO may be the principal endothelial vasodilator substance in big artery.
authors.affiliation: Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China.
authors.forename: Guo-Dong
authors.initials: GD
authors.lastname: Jia
authors.forename: Chao-Liang
authors.initials: CL
authors.lastname: Long
authors.forename: Guo-Shu
authors.initials: GS
authors.lastname: Liu
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000187:drug effects*; D001158:Arteries / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation / Q000187:drug effects
chemical_list: D000109:Acetylcholine