Vascular oxidative metabolism under different metabolic conditions.
Control of respiration in vascular smooth muscle was examined while the metabolic state of the tissue was manipulated. During KCl-induced contractures in the presence of 5 mM glucose, oxygen consumption increased by 10 nmol/per min g without any decrease in phosphocreatine (PCr) or ATP as determined by 31P-NMR indicating a control of respiration which does not involve changes in high-energy phosphates (e.g., ADP, phosphorylation potential). However, when aortae with resting tone in the absence of substrate were then provided with 5 mM 2-deoxyglucose as the sole substrate, oxygen consumption increased 7.4 nmol/min per g while PCr decreased by more than 50% (resulting in a 2-fold increase in the calculated free ADP) with no change in tension from resting tone. During a subsequent KCl induced contracture in the presence of 2-deoxyglucose, oxygen consumption increased an additional 7.2 nmol/min per g while PCr continued to decline. Therefore, at least two mechanisms of respiratory control may exist in sheep aorta, one dependent and the other independent of changes in high-energy phosphates.
Hardin
C D
CD
Department of Radiology, University of Washington, Seattle.
Wiseman
R W
RW
Kushmerick
M J
MJ
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001013:Aorta, Thoracic; D003847:Deoxyglucose / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D010101:Oxygen Consumption; D010725:Phosphocreatine / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D012756:Sheep
D010725:Phosphocreatine; D000244:Adenosine Diphosphate; D011189:Potassium Chloride; D000255:Adenosine Triphosphate; D003847:Deoxyglucose; D005947:Glucose