title: Tempol attenuates the exercise pressor reflex independently of neutralizing reactive oxygen species in femoral artery ligated rats.
abstract: In decerebrate rats, we reported previously that the exercise pressor reflex arising from a limb whose femoral artery was occluded for 72 h before the experiment was significantly higher than the exercise pressor reflex arising from a contralateral freely perfused limb. These findings prompted us to examine whether reactive oxygen species contributed to the augmented pressor reflex in rats with femoral artery occlusion. We found that the pressor reflex arising from the limb whose femoral artery was occluded for 72 h before the experiment (31 ± 5 mmHg) was attenuated by tempol (10 mg), a superoxide dismutase (SOD) mimetic (18 ± 5 mmHg, n = 9, P < 0.05), that was injected into the arterial supply of the hindlimb. In contrast, the pressor reflex arising from a freely perfused hindlimb (20 ± 3 mmHg) was not attenuated by tempol (17 ± 4 mmHg, n = 10, P = 0.49). Nevertheless, we found no difference in the increase in 8-isoprostaglandin F(2α) levels, an index of reactive oxygen species, in response to contraction between freely perfused (3.76 ± 0.82 pg/ml, n = 19) and 72-h occluded (3.51 ± 0.92 pg/ml, n = 22, P = 0.90) hindlimbs. Moreover, tempol did not reduce the 8-isoprostaglandin F(2α) levels during contraction in either group (P > 0.30). A second SOD mimetic, tiron (200 mg/kg), had no effect on the exercise pressor reflex in either the rats with freely perfused hindlimbs or in those with occluded femoral arteries. These findings suggest that tempol attenuated the exercise pressor reflex in the femoral artery-occluded hindlimb by a mechanism that was independent of its ability to scavenge reactive oxygen species.
authors: Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA.
authors: Jennifer L
authors: JL
authors: McCord
authors: Hirotsugu
authors: H
authors: Tsuchimochi
authors: Katsuya
authors: K
authors: Yamauchi
authors: Anna
authors: A
authors: Leal
authors: Marc P
authors: MP
authors: Kaufman
mesh_terms: D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / Q000494:pharmacology; D000818:Animals; D003497:Cyclic N-Oxides / Q000494:pharmacology*; D003655:Decerebrate State / Q000378:metabolism; D015237:Dinoprost / Q000031:analogs & derivatives / Q000378:metabolism; D005263:Femoral Artery / Q000187:drug effects* / Q000378:metabolism / Q000601:surgery; D006614:Hindlimb / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D008026:Ligation / Q000379:methods; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D010805:Physical Conditioning, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012018:Reflex / Q000187:drug effects / Q000502:physiology; D013113:Spin Labels; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D003497:Cyclic N-Oxides; D017382:Reactive Oxygen Species; D013113:Spin Labels; C075750:8-epi-prostaglandin F2alpha; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D015237:Dinoprost; D013482:Superoxide Dismutase; C001803:tempol