JOURNAL ARTICLE

Androgen deprivation facilitates acetylcholine-induced relaxation by superoxide anion generation

M Ferrer, N Tejera, J Marín, G Balfagón
Clinical Science (1979-) 1999, 97 (6): 625-31
10585889
The aim of the present study was to assess the role of superoxide anions in the relaxation induced by acetylcholine (ACh) in aortic segments from male rats, and to investigate if their production is altered by sex hormone deprivation. In segments precontracted with 10 nmol/l noradrenaline, ACh (0.1 nmol/l-10 micromol/l) induced concentration-dependent relaxation, which was greater in segments from castrated compared with control animals. ACh-induced relaxation was abolished in segments from control rats, and reduced in those from castrated rats, by 0.1 mmol/l N(G)-nitro-L-arginine methyl ester (L-NAME; a nitric oxide synthase inhibitor). Indomethacin (1 micromol/l; a cyclo-oxygenase blocker) decreased the ACh-induced relaxation in arteries from control males only. Incubation of segments with superoxide dismutase (SOD; 100 units/ml; a superoxide anion scavenger) enhanced and reduced relaxation in segments from control and castrated animals respectively. For arteries from castrated animals, the presence of SOD plus L-NAME abolished such responses. In these arteries, incubation with L-NAME abolished the relaxation caused by ACh when the segments were precontracted with 30 mmol/l KCl. In segments obtained from castrated rats and pretreated with L-NAME, 1 mmol/l tetraethylammonium or 0.4 micromol/l charybdotoxin [blockers of Ca(2+)-sensitive and large-conductance Ca(2+)-sensitive (BK(Ca)) K(+) channels respectively] abolished the relaxation induced by ACh. These results suggest that ACh generates endothelial NO and superoxide anions from the arterial wall in both control and castrated animals; these agents negatively modulate ACh-induced relaxation in control rats by destruction of NO, and positively modulate ACh-induced relaxation in castrated rats by activation of BK(Ca) channels.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read
10585889
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"