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HYDROGEN PEROXIDE CENTRALLY REDUCES THE PRESSOR RESPONSE TO ANGIOTENSIN II IN HYPERTENSIVE RATS
Author(s) -
Lauar Mariana Ruiz,
Paula Patricia Maria,
Cardoso Leonardo Máximo,
Colombari Débora S.A.,
Colombari Eduardo,
Menani José Vanderlei
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.843.19
Previous studies have shown that intracerebroventricular (icv) injection of hydrogen peroxide (H 2 O 2 ) or the catalase inhibitor 3‐amino‐1,2,4‐triazole (ATZ) reduces the pressor responses to icv angiotensin II (ANG II) in normotensive rats. In the present study, we investigated the effects of icv injection of H 2 O 2 alone or combined with ATZ intravenously (iv) on the pressor responses to icv ANG II in spontaneously hypertensive rats (SHR). Mean arterial pressure (MAP) and heart rate (HR) were recorded in unanesthetized SHR (300–370 g, baseline MAP 178 ± 3 mmHg and HR 362 ± 6 bpm, n=6–10/group) with stainless steel cannulas implanted in the lateral ventricle (LV). The previous icv injection of H 2 O 2 (5 μmol/1 μl) alone or combined with ATZ (300 mg/kg of body weight) iv similarly reduced the pressor response to ANG II (50 ng/1 μl) icv (11 ± 3 and 9 ± 1 mmHg, respectively, vs.: vehicle: 22 ± 5 mmHg). Injection of H 2 O 2 icv or ATZ iv alone produced no significant change on baseline MAP (−9 ± 2 and −7 ± 1 mmHg, respectively, vs. vehicle: −3 ± 1 mmHg), however, combining ATZ iv with H 2 O 2 icv reduced baseline MAP (−13 ± 2 mmHg). These treatments produced no significant change on HR. The results show that icv injections of H 2 O 2 alone or combined with ATZ iv reduced the pressor response to central ANG II and the combination of ATZ iv with H 2 O 2 icv also reduced baseline MAP in SHR. Supported by: FAPESP, CNPq