Mitochondrial aldehyde dehydrogenase mediates vasodilator responses of glyceryl trinitrate and sodium nitrite in the pulmonary vascular bed of the rat.
It has been reported that mitochondrial aldehyde dehydrogenase (ALDH2) catalyzes the formation of glyceryl dinitrate and inorganic nitrite from glyceryl trinitrate (GTN), leading to an increase in cGMP and vasodilation in the coronary and systemic vascular beds. However, the role of nitric oxide (NO) formed from nitrite in mediating the response to GTN in the pulmonary vascular bed is uncertain. The purpose of the present study was to determine if nitrite plays a role in mediating vasodilator responses to GTN. In this study, intravenous injections of GTN and sodium nitrite decreased pulmonary and systemic arterial pressures and increased cardiac output. The decreases in pulmonary arterial pressure under baseline and elevated tone conditions and decreases in systemic arterial pressure in response to GTN and sodium nitrite were attenuated by cyanamide, an ALDH2 inhibitor, whereas responses to the NO donor, sodium nitroprusside (SNP), were not altered. The decreases in pulmonary and systemic arterial pressure in response to GTN and SNP were not altered by allopurinol, an inhibitor of xanthine oxidoreductase, whereas responses to sodium nitrite were attenuated. GTN was approximately 1,000-fold more potent than sodium nitrite in decreasing pulmonary and systemic arterial pressures. These results suggest that ALDH2 plays an important role in the bioactivation of GTN and nitrite in the pulmonary and systemic vascular beds and that the reduction of nitrite to vasoactive NO does not play an important role in mediating vasodilator responses to GTN in the intact chest rat.
Badejo
Adeleke M
AM
Department of Pharmacology, Tulane University School of Medicine, New Orleans 70112-2699, USA.
Hodnette
Chris
C
Dhaliwal
Jasdeep S
JS
Casey
David B
DB
Pankey
Edward
E
Murthy
Subramanyam N
SN
Nossaman
Bobby D
BD
Hyman
Albert L
AL
Kadowitz
Philip J
PJ
D000444:Aldehyde Dehydrogenase / Q000378:metabolism*; D000071396:Aldehyde Dehydrogenase, Mitochondrial; D000704:Analysis of Variance; D000818:Animals; D003484:Cyanamide / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008168:Lung / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D005996:Nitroglycerin / Q000378:metabolism* / Q000494:pharmacology; D011652:Pulmonary Circulation / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012977:Sodium Nitrite / Q000378:metabolism* / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology
D004791:Enzyme Inhibitors; D024101:Mitochondrial Proteins; D014665:Vasodilator Agents; D009569:Nitric Oxide; D003484:Cyanamide; D000444:Aldehyde Dehydrogenase; D000071396:Aldehyde Dehydrogenase, Mitochondrial; C505112:Aldh2 protein, rat; D005996:Nitroglycerin; D012977:Sodium Nitrite; D019331:NG-Nitroarginine Methyl Ester