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Autonomic mechanisms underpinning the stress response in borderline hypertensive rats
Author(s) -
Sarenac Olivera,
Lozic Maja,
Drakulic Srdja,
Bajic Dragana,
Paton Julian F.,
Murphy David,
JapundzicZigon Nina
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.1027.12
Subject(s) - baroreflex , medicine , heart rate variability , blood pressure , shaker , heart rate , basal (medicine) , cardiology , diastole , endocrinology , physics , vibration , quantum mechanics , insulin
This study investigates blood pressure (BP) and heart rate (HR) short‐term variability and spontaneous baroreflex functioning in adult borderline hypertensive rats (BHR) and normotensive controls (NC). Systolic BP, diastolic BP and HR variabilities and baroreflex were assessed by spectral analysis and the sequence method respectively. In all experimental conditions BHR exhibited higher BP, increased baroreflex sensitivity and resetting, relative to controls. Acute shaker stress increased BP in both strains while chronic shaker stress increased BP in BHR alone. Low frequency and high frequency HR variability increased only in controls to acute and chronic shaker stress. Acute restraint stress increased BP, HR, low frequency and high frequency variability of BP and HR in both strains. Only NC exhibited reduced ratio of low‐to‐high frequency HR variability, pointing to domination of vagal cardiac control. In BHR, but not in controls, chronic restraint stress increased low frequency and high frequency BP and HR variability and their ratio indicating a shift towards sympathetic cardiovascular control. It is concluded that maintenance of BP in BHR under basal conditions and stress is associated with enhanced baroreflex sensitivity and resetting. Imbalance in sympatho‐vagal control was evident only during exposure of BHR to stressors. Research supported: Wellcome Trust, Royal Society and Ministry of Science.