Compensation of endothelium-dependent responses in coronary circulation of eNOS-deficient mice.
Nitric oxide plays a fundamental role in the regulation of blood flow. Here we analyzed compensatory mechanisms for the genetic eNOS deficiency in aorta and in coronary circulation. Vasodilation induced by acetylcholine, bradykinin, adenosine, and ADP as well as by S-nitroso-penicillamine (SNAP) was assessed in isolated aorta and in isolated mouse hearts from eNOS-/- and age-matched eNOS+/+ mice. In aorta from eNOS+/+ mice acetylcholine-induced vasodilation was entirely dependent on NO, and this response was absent in aorta from eNOS-/- mice. In eNOS+/+ mouse hearts responses induced by bradykinin, adenosine and ADP were partially dependent on NO, but not on PGI2, cytochrome P450-dependent metabolites, or H2O2. On the other hand, vasodilation induced by acetylcholine involved NO, but not PGI2, in its immediate, short-lasting phase, whereas PGI2 and NO mediated delayed, longer-lasting phase of this response. In eNOS-/- mouse hearts coronary vasodilator function was compensated. Responses induced by acetylcholine and adenosine, but not by bradykinin or ADP, were in part compensated by NO, most likely derived from nNOS. However, the major mechanisms compensating for the loss of eNOS in the coronary circulation did not rely on NO, PGI2, cytochrome P450-derived metabolites of arachidonic acid or on H2O2. Deficiency of eNOS is largely compensated in coronary circulation but not in aorta.
Chlopicki
Stefan
S
Department of Experimental Pharmacology, Jagiellonian University Medical College, Krakow, Poland. mfschlop@cyf-kr.edu.pl
Kozlovski
Valery I
VI
Lorkowska
Barbara
B
Drelicharz
Lukasz
L
Gebska
Anna
A
D015121:6-Ketoprostaglandin F1 alpha / Q000378:metabolism; D000109:Acetylcholine / Q000494:pharmacology; D000222:Adaptation, Physiological; D000241:Adenosine / Q000494:pharmacology; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000367:Age Factors; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D001920:Bradykinin / Q000494:pharmacology; D003326:Coronary Circulation / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D005838:Genotype; D006321:Heart / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009206:Myocardium / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000172:deficiency* / Q000235:genetics; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
D014665:Vasodilator Agents; D015121:6-Ketoprostaglandin F1 alpha; D000244:Adenosine Diphosphate; D052250:Nitric Oxide Synthase Type III; D000241:Adenosine; D000109:Acetylcholine; D001920:Bradykinin