Role of EDRFs in the control of arteriolar diameter during increased metabolism of striated muscle.
This experiment was designed to determine the role that the release of endothelium-derived relaxing factors (EDRFs), endothelium-derived nitric oxide (EDNO), or prostaglandins have in the control of arteriolar vasodilation during an increased metabolic rate in striated muscle. A silicone stopcock grease dam was placed across the distal portion of the cremaster muscle of pentobarbital-anesthetized hamsters to localize the application of the metabolic stimulator 2,4-dinitrophenol (DNP). Application of DNP (10 mM) to the distal region resulted in significant increases in red cell velocity (from 6 +/- 1 to 10 +/- 2 mm/s) and arteriolar diameter (from 75 +/- 3 to 91 +/- 5 microns) (P < 0.05; n = 6) in the first-order arterioles located approximately 11 mm upstream from the silicone dam. Administration of N omega-nitro-L-arginine methyl ester (L-NAME; 2 mg iv) resulted in significant vasoconstriction of the first-order arterioles and a significant decrease in the vasodilator response to acetylcholine (1 microM). Addition of sodium nitroprusside (380 microM) to the superfusion solution during L-NAME treatment resulted in a return of arteriolar diameter to control levels. DNP treatment during L-NAME and sodium nitroprusside treatment did not inhibit the arteriolar vasodilation [75 +/- 3 to 87 +/- 4 microns (P > 0.05)] after a significant increase in red cell velocity from 7 +/- 1 to 11 +/- 1 mm/s. Before indomethacin treatment, DNP treatment resulted in an increase in arteriolar diameter from 72 +/- 3 to 90 +/- 3 microns, preceded by an increase in red cell velocity from 6 +/- 1 to 10 +/- 1 mm/s.(ABSTRACT TRUNCATED AT 250 WORDS)
Saito
Y
Y
Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson 39216-4505.
Eraslan
A
A
Hester
R L
RL
D019297:2,4-Dinitrophenol; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001160:Arterioles / Q000502:physiology*; D006224:Cricetinae; D004140:Dinitrophenols / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D008647:Mesocricetus; D009132:Muscles / Q000378:metabolism*; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D014664:Vasodilation / Q000502:physiology*
D004140:Dinitrophenols; D011448:Prostaglandin Antagonists; D009569:Nitric Oxide; D001120:Arginine; D019297:2,4-Dinitrophenol; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin