Experimental Addition | Relaxation2-a | |||
---|---|---|---|---|
CGRP | Cromakalim | |||
T12-b | T22-b | T12-b | T22-b | |
% | % | % | % | |
None | 89.8 ± 7.1 | 91.4 ± 3.6 | 93.6 ± 12.8 | 90.8 ± 8.2 |
H2O2 | 92.0 ± 5.0 | 88.6 ± 4.5 | 82.4 ± 7.6 | 80.8 ± 6.0 |
FeSO4 | 81.4 ± 4.3 | 92.1 ± 5.3 | 91.2 ± 8.3 | 84.3 ± 4.1 |
H2O2 + FeSO4 | 79.3 ± 8.7 | 18.3 ± 2.8* | 84.4 ± 6.9 | 20.0 ± 14.2* |
Catalase | 88.2 ± 6.8 | 87.3 ± 5.0 | 92.6 ± 8.5 | 91.4 ± 4.5 |
DMTU | 83.3 ± 10.5 | 90.3 ± 6.2 | 90.9 ± 5.3 | 86.6 ± 8.0 |
DMSO | 84.9 ± 6.9 | 80.3 ± 8.4 | 84.4 ± 9.9 | 80.1 ± 3.9 |
Deferoxamine | 80.9 ± 11.2 | 85.8 ± 3.3 | 81.2 ± 10.8 | 89.0 ± 5.3 |
Catalase + H2O2 + FeSO4 | 90.6 ± 8.8 | 65.2 ± 9.2†† | 91.6 ± 11.7 | 71.2 ± 5.1†† |
DMTU + H2O2 + FeSO4 | 82.7 ± 9.2 | 69.6 ± 4.8†† | 82.0 ± 8.1 | 63.3 ± 3.3† |
DMSO + H2O2 + FeSO4 | 92.0 ± 5.6 | 76.1 ± 3.6†† | 86.5 ± 5.5 | 70.3 ± 8.6† |
Deferoxamine + H2O2 + FeSO4 | 81.1 ± 7.2 | 63.8 ± 4.9†† | 86.6 ± 8.2 | 73.4 ± 9.6† |
Catalase/deferoxamine + H2O2 + FeSO4 | 90.8 ± 9.4 | 79.1 ± 5.0†† | 91.5 ± 7.4 | 81.0 ± 10.2†† |
The endothelium-denuded rings were previously treated with guanethidine (5 × 10−6 M), and the effect was confirmed in all rings before the start of the experiments; the denudation of the endothelium was also checked (see fig. 2, legend). Exposure to H2O2/FeSO4 reaction of the ring preparations was performed under the same conditions as those of figures 4A and 5A, except that the scavengers used were added 1 min before the addition of H2O2/FeSO4 to the bathing medium. Mean values ± S.E.M. (n = 5–6) are shown;n refers to the number of dogs from which the lingual artery was taken. When added, doses were: 3 × 10−4 M H2O2, 2 × 10−4 M FeSO4, 100 U/ml catalase, 1 mM DMTU, 100 mM DMSO, 1 mM deferoxamine, 10−8 M CGRP and 10−6 M cromakalim.
↵2-a The relaxant response of the rings precontracted with NE (10−5 M) was expressed as a percentage of the maximum relaxation induced by 2 × 10−4 M papaverine applied at the end of the experiments.
↵2-b T1 and T2 show the relaxation induced by first test (T1) and second test (T2) of CGRP or cromakalim; T1, relaxation before the experimental treatment; T2, relaxation after the experimental treatment.
* Significantly (P < .01) different from corresponding value from none-control; †, †† significantly (†P < .05; ††P < .01) different from corresponding value for H2O2 + FeSO4.