Differences in EDNO contribution to arteriolar diameters at rest and during functional dilation in striated muscle.
This study was designed to determine the physiological role of endothelium-dependent nitric oxide (EDNO) in the control of arteriolar diameter during rest and muscle stimulation. Diameters of first-, second-, and third-order arterioles in the superfused hamster cremaster muscle were measured before and throughout 1 min of field stimulation before and after inhibition of EDNO release. ENDO inhibition by intravenous N omega-nitro-L-arginine methyl ester (L-NAME) significantly attenuated the arteriolar vasodilation in response to 1 microM acetylcholine. First-order arterioles averaged 65 +/- 5 microns at rest and dilated to 86 +/- 6 microns during muscle stimulation (n = 9), second-order arterioles averaged 45 +/- 6 microns and dilated to 72 +/- 3 microns during muscle stimulation (n = 6), with third-order arterioles averaging 29 +/- 2 microns, and dilating to 53 +/- 3 microns during muscle stimulation (n = 7). EDNO inhibition significantly decreased both the resting diameter of first-order arterioles (57 +/- 4 microns) and functional dilation (68 +/- 3 microns; P < 0.05). EDNO inhibition had no effect on the resting diameter of second-order arterioles (45 +/- 5 microns) yet significantly attenuated the functional dilation (64 +/- 4 microns; P < 0.05). EDNO inhibition had no effect on either the resting diameter of third-order arterioles (30 +/- 2 microns) or the functional dilation (49 +/- 2 microns).(ABSTRACT TRUNCATED AT 250 WORDS)
Hester
R L
RL
Department of Physiology, University of Mississippi Medical Center, Jackson 39216-4505.
Eraslan
A
A
Saito
Y
Y
D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001160:Arterioles / Q000502:physiology; D006224:Cricetinae; D004558:Electric Stimulation; D004730:Endothelium, Vascular / Q000502:physiology*; D008297:Male; D008647:Mesocricetus; D009132:Muscles / Q000098:blood supply*; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000494:pharmacology*; D012146:Rest; D013997:Time Factors; D014664:Vasodilation
D009569:Nitric Oxide; D001120:Arginine; D000241:Adenosine; D019331:NG-Nitroarginine Methyl Ester