scholarly journals Chronic nicotine treatment enhances vascular smooth muscle relaxation in rats

2015 ◽  
Vol 36 (4) ◽  
pp. 429-439 ◽  
Author(s):  
Tian-ying Xu ◽  
Xiao-hong Lan ◽  
Yun-feng Guan ◽  
Sai-long Zhang ◽  
Xia Wang ◽  
...  
1991 ◽  
Vol 260 (3) ◽  
pp. H698-H701 ◽  
Author(s):  
J. L. Dinerman ◽  
D. L. Lawson ◽  
J. L. Mehta

To evaluate the role of endothelium in nitroglycerin (NTG)-mediated vascular relaxation, epinephrine-contracted rat thoracic aortic segments with and without intact endothelium were exposed to NTG (10(-10) to 10(-5) M). Aortic segments with intact (endo+, n = 15) and denuded endothelium (endo-, n = 9) exhibited typical NTG-induced relaxation. However, the mean effective concentration of NTG was lower for endo- than for endo+ segments (P less than 0.001). To determine if this phenomenon related to nitric oxide (NO) generation by endothelium, six endo+ segments were treated with NG-monomethyl-L-arginine (L-NMMA), an inhibitor of NO production. These endo+ segments exhibited greater (P less than 0.001) relaxation in response to NTG than the untreated endo+ segments. Oxyhemoglobin, an inhibitor of guanylate cyclase activation, greatly diminished NTG-mediated relaxation of all aortic segments. To determine if the enhanced NTG-mediated relaxation of endo- segments was unique to the guanosine 3',5'-cyclic monophosphate-dependent vasodilator NTG, other endo+ and endo- segments were exposed to adenosine 3',5'-cyclic monophosphate-dependent vasodilator papaverine (10(-8) to 10(-4) M), and no difference in EC50 was noted between endo+ and endo- segments. Thus endothelium attenuates NTG-mediated vasorelaxation, and this attenuation is abolished by inhibition of endothelial NO production with L-NMMA. These observations indicate that endothelium is a dynamic modulator of vascular smooth muscle relaxant effects of NTG. This modulation appears to result from a competitive interaction between endothelial NO and NTG.


1996 ◽  
Vol 61 (2) ◽  
pp. 444-448 ◽  
Author(s):  
David A. Fullerton ◽  
Jeanette Agrafojo ◽  
Robert C. McIntyre, Jr.

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