Age-associated changes in large blood vessels were characterized by increased arterial wall thickness, luminal dilation and impaired endothelial function. But little is known about the effect of age on structural and functional changes in small resistance arteries. The mechanisms underlying age-associated endothelial dysfunction in rat mesenteric resistance arteries were investigated in the present study. Small rat mesenteric arteries were excised and cannulated, and vascular endothelial functions were tested by acetylcholine (ACh). Our experiments showed (1) endotheliumdependent vasorelaxation induced by ACh was reduced in aged mesenteric arteries; (2) blockade of Kca channels markedly reduced the vasodilation in young and adult rats, the resultant reduction in aged rats was much smaller compared with young and adult rats; (3) inhibition of endothelial nitric oxide synthase (NOS) resulted in a significant reduction of vasodilation in young and adult, but there was a smaller reduction in aged rats. The results suggest that (1) endothelial function was impaired in mesenteric arteries of aged rats; (2) both Kca channels and nitric oxide (NO) contribute together to the ACh-induced vasorelaxation in small mesenteric arteries, and (3) both the impairment of Kca channel function and decreased NO account for the age-related endothelial dysfunction.
- MeSH
- acetylcholin farmakologie MeSH
- apamin farmakologie MeSH
- arteriae mesentericae metabolismus patofyziologie účinky léků MeSH
- blokátory draslíkových kanálů farmakologie MeSH
- cévní endotel metabolismus patofyziologie účinky léků MeSH
- charybdotoxin farmakologie MeSH
- draslíkové kanály aktivované vápníkem antagonisté a inhibitory metabolismus MeSH
- inhibitory enzymů farmakologie MeSH
- krysa rodu rattus MeSH
- omega-N-methylarginin farmakologie MeSH
- oxid dusnatý metabolismus MeSH
- potkani Sprague-Dawley MeSH
- stárnutí metabolismus MeSH
- synthasa oxidu dusnatého, typ III antagonisté a inhibitory metabolismus MeSH
- techniky in vitro MeSH
- vazodilatace účinky léků MeSH
- vazodilatancia farmakologie MeSH
- věkové faktory MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
