Details

Autor(en) / Beteiligte

• Lantelme, Pierre
• Cerutti, Catherine
• Lo, Ming
• Paultre, Christian Z
• Ducher, Michel

Titel

Mechanisms of spontaneous baroreflex impairment in Lyon hypertensive rats

Ist Teil von

• American journal of physiology. Regulatory, integrative and comparative physiology, 1998-09, Vol.275 (3), p.R920

Ort / Verlag

United States

Erscheinungsjahr

1998

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• This experiment aimed at 1) comparing the spontaneous baroreflex sensitivity (SBRS) in Lyon genetically hypertensive (LH), normotensive (LN), and low blood pressure (LL) rats and 2) assessing some aspects of the mechanisms of its impairment in LH rats. Baroreflex was studied in control animals after an early chronic converting enzyme inhibition with perindopril and after a 4-wk infusion of ANG II in perindopril-treated rats. The SBRS was determined with a previously validated method, using statistical dependence between blood pressure (BP) and heart rate values recorded in freely moving animals. LH rats exhibited high BP, cardiac hypertrophy, and decreased SBRS (LH, 1.3 ± 0.2; LN, 2.5 ± 0.4; LL, 2.2 ± 0.4 beats ⋅ min ⋅ mmHg ). Perindopril prevented the development of hypertension and cardiac hypertrophy and normalized SBRS. BP rose in LH and LL rats after ANG II infusion, but only LH rats, which developed a cardiac hypertrophy, had an impaired SBRS (LH, 1.1 ± 0.2; LN, 2.5 ± 0.2; LL, 2.8 ± 0.3 beats ⋅ min ⋅ mmHg ). This impairment was partially reversed by an acute ANG II blockade with losartan. These results demonstrate that high BP does not account for the decreased SBRS in LH rats. SBRS impairment could result either from cardiac hypertrophy or from the direct effect of ANG II on the baroreflex loop.