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Antioxidant enzymes and effects of tempol on the development of hypertension induced by nitric oxide inhibition.
Am J Hypertens. 2005 Jun; 18(6):871-7.AJ

Abstract

BACKGROUND

This study analyzed whether hypertension induced by N(omega)-nitro-l-arginine methyl ester (L-NAME) is associated with dysregulation of the main antioxidant enzymes (superoxide dismutase [SOD], catalase, glutathione peroxidase [GPX], and glutathione reductase [GR]) and whether chronic administration of tempol ameliorates this hypertension.

METHODS

Four groups of male Wistar rats were used: 1) control rats; 2) rats treated with L-NAME (35 mg/100 mL in drinking fluid); 3) rats treated with tempol (18 mg/100 mL in drinking fluid); and 4) rats treated with L-NAME plus tempol. All treatments were maintained for 6 weeks. Body weight, systolic blood pressure (BP) determined by the tail-cuff method, and heart rate were measured once per week. At the end of the experimental period, direct BP and morphologic, metabolic, plasma, and renal variables were measured. Enzymatic activities were measured in the kidney (cortex and medulla) and heart (right and left ventricles).

RESULTS

Rats with L-NAME-induced hypertension showed increased copper-zinc (Cu-Zn) SOD activity in the renal cortex and medulla and the left and right ventricles, which was reduced by tempol administration. The manganese (Mn) SOD activity was increased by L-NAME and reduced by tempol in the renal cortex but was unchanged in other tissues. Catalase activity was not affected by L-NAME or tempol treatments in any tissue. Both GPX and GR activities were increased by L-NAME and reduced by tempol in the renal cortex and medulla but were not affected in the ventricles. Tempol reduced BP and total urinary excretion of 8-hydroxy-2'-deoxyguanosine in L-NAME-treated animals but did not affect either variable in controls.

CONCLUSIONS

We conclude that L-NAME-induced hypertension is associated with an upregulation of antioxidant SOD, GPX, and GR activities. Moreover, the results indicate that tempol attenuates hypertension on nitric oxide-deficient rats and that oxidative stress participates in the established phase of this type of hypertension.

Authors+Show Affiliations

Departamento de Fisiología, Facultad de Medicina, Granada, Spain.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15925750

Citation

Sainz, Juan, et al. "Antioxidant Enzymes and Effects of Tempol On the Development of Hypertension Induced By Nitric Oxide Inhibition." American Journal of Hypertension, vol. 18, no. 6, 2005, pp. 871-7.
Sainz J, Wangensteen R, Rodríguez Gómez I, et al. Antioxidant enzymes and effects of tempol on the development of hypertension induced by nitric oxide inhibition. Am J Hypertens. 2005;18(6):871-7.
Sainz, J., Wangensteen, R., Rodríguez Gómez, I., Moreno, J. M., Chamorro, V., Osuna, A., Bueno, P., & Vargas, F. (2005). Antioxidant enzymes and effects of tempol on the development of hypertension induced by nitric oxide inhibition. American Journal of Hypertension, 18(6), 871-7.
Sainz J, et al. Antioxidant Enzymes and Effects of Tempol On the Development of Hypertension Induced By Nitric Oxide Inhibition. Am J Hypertens. 2005;18(6):871-7. PubMed PMID: 15925750.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Antioxidant enzymes and effects of tempol on the development of hypertension induced by nitric oxide inhibition. AU - Sainz,Juan, AU - Wangensteen,Rosemary, AU - Rodríguez Gómez,Isabel, AU - Moreno,Juan Manuel, AU - Chamorro,Virginia, AU - Osuna,Antonio, AU - Bueno,Pablo, AU - Vargas,Félix, PY - 2004/07/13/received PY - 2004/11/10/revised PY - 2004/12/03/accepted PY - 2005/6/1/pubmed PY - 2005/9/16/medline PY - 2005/6/1/entrez SP - 871 EP - 7 JF - American journal of hypertension JO - Am J Hypertens VL - 18 IS - 6 N2 - BACKGROUND: This study analyzed whether hypertension induced by N(omega)-nitro-l-arginine methyl ester (L-NAME) is associated with dysregulation of the main antioxidant enzymes (superoxide dismutase [SOD], catalase, glutathione peroxidase [GPX], and glutathione reductase [GR]) and whether chronic administration of tempol ameliorates this hypertension. METHODS: Four groups of male Wistar rats were used: 1) control rats; 2) rats treated with L-NAME (35 mg/100 mL in drinking fluid); 3) rats treated with tempol (18 mg/100 mL in drinking fluid); and 4) rats treated with L-NAME plus tempol. All treatments were maintained for 6 weeks. Body weight, systolic blood pressure (BP) determined by the tail-cuff method, and heart rate were measured once per week. At the end of the experimental period, direct BP and morphologic, metabolic, plasma, and renal variables were measured. Enzymatic activities were measured in the kidney (cortex and medulla) and heart (right and left ventricles). RESULTS: Rats with L-NAME-induced hypertension showed increased copper-zinc (Cu-Zn) SOD activity in the renal cortex and medulla and the left and right ventricles, which was reduced by tempol administration. The manganese (Mn) SOD activity was increased by L-NAME and reduced by tempol in the renal cortex but was unchanged in other tissues. Catalase activity was not affected by L-NAME or tempol treatments in any tissue. Both GPX and GR activities were increased by L-NAME and reduced by tempol in the renal cortex and medulla but were not affected in the ventricles. Tempol reduced BP and total urinary excretion of 8-hydroxy-2'-deoxyguanosine in L-NAME-treated animals but did not affect either variable in controls. CONCLUSIONS: We conclude that L-NAME-induced hypertension is associated with an upregulation of antioxidant SOD, GPX, and GR activities. Moreover, the results indicate that tempol attenuates hypertension on nitric oxide-deficient rats and that oxidative stress participates in the established phase of this type of hypertension. SN - 0895-7061 UR - https://www.unboundmedicine.com/medline/citation/15925750/Antioxidant_enzymes_and_effects_of_tempol_on_the_development_of_hypertension_induced_by_nitric_oxide_inhibition_ L2 - https://academic.oup.com/ajh/article-lookup/doi/10.1016/j.amjhyper.2004.12.022 DB - PRIME DP - Unbound Medicine ER -