Selected Contribution: Aging impairs nitric oxide and prostacyclin mediation of endothelium-dependent dilation in soleus feed arteries.
We tested the hypothesis that endothelium-dependent dilation in soleus muscle feed arteries (SFA) is impaired by aging due to attenuated nitric oxide (NO)-mediated vasodilation. SFA were isolated from young (4 mo) and old (24 mo) male Fischer 344 rats and cannulated with two glass micropipettes for examination of endothelium-dependent [flow or acetylcholine (ACh)] and endothelium-independent [sodium nitroprusside (SNP)] vasodilator function. Flow- and ACh-induced dilation was significantly attenuated by age, whereas dilation to SNP was not compromised. To determine the mechanism(s) by which aging affected dilator responses to flow and ACh, dilation was assessed in the presence of Nomega-nitro-L-arginine (L-NNA; to inhibit NO synthase), indomethacin (Indo; to inhibit cyclooxygenase), and L-NNA + Indo. In the presence of L-NNA, Indo, or L-NNA + Indo, flow-induced dilation was inhibited in young SFA, resulting in a response to flow that was no longer greater than old SFA. In the presence of L-NNA or Indo, ACh-induced dilation was not significantly inhibited in young or old SFA; however, double blockade with L-NNA + Indo inhibited ACh-induced dilation in young SFA such that the response to ACh was no longer greater than old SFA. Collectively, these data indicate that aging impairs vasodilator responses in SFA by attenuating NO- and prostacyclin-mediated, endothelium-dependent, dilation.
Woodman
Christopher R
CR
Deparment of Biomedical Sciences, University of Missouri, Columbia, Missouri 65211, USA. woodmanc@missouri.edu
Price
Elmer M
EM
Laughlin
M Harold
MH
D000109:Acetylcholine / Q000494:pharmacology; D000375:Aging / Q000378:metabolism*; D000818:Animals; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D011464:Epoprostenol / Q000378:metabolism*; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply*; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D019335:Nitroarginine / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D014665:Vasodilator Agents; D009599:Nitroprusside; D019335:Nitroarginine; D009569:Nitric Oxide; D011464:Epoprostenol; D019001:Nitric Oxide Synthase; D000109:Acetylcholine; D007213:Indomethacin