[The autoregulation of the coronary flow of the isolated rat heart after NO-synthase blockade].
The experiments were performed on 67 rat hearts isolated by the Langendorff method. Perfusion pressure (PP) was stepwise increased from 40 to 120 mm Hg. It was found that NO-synthase blockade by NG-monomethyl-L-arginine (NG-MMLA) decreased volume velocity coronary flow (VVCF) at PP 40 and 60 mm Hg, autoregulation index and shifted the onset of effective autoregulation to the right. In cases of high coronary tone, caused by introduction of pituitrine, the autoregulation and its effectiveness was unchanged. The combination of NG-MMLA and pituitrine decreased the autoregulation index again. In cardiac perfusion under constant pressure, the value of maximal hyperemic coronary flow after introduction of NG-MMLA was decreased by 30-57%, and as a result the coronary reserve was decreased by 28.3%. Thus, NO, which released from endothelium of coronary vessels plays a significant role in mechanism of coronary autoregulation.
Solodkov
A P
AP
Bozhko
A P
AP
Shebeko
V I
VI
Rodionov
Iu Ia
IuIa
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors* / Q000187:drug effects; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001783:Blood Flow Velocity / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006706:Homeostasis / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D009569:Nitric Oxide / Q000037:antagonists & inhibitors; D019001:Nitric Oxide Synthase; D010477:Perfusion / Q000379:methods; D010909:Pituitary Hormones, Posterior / Q000494:pharmacology; D051381:Rats; D019323:omega-N-Methylarginine
D010909:Pituitary Hormones, Posterior; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases