Departamento de Fisiologia, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
Braz J Med Biol Res. 2010 Oct;43(10):969-75. doi: 10.1590/s0100-879x2010007500105. Epub 2010 Oct 8.
The low incidence of cardiovascular diseases, including hypertension, in premenopausal women has led to the conclusion that ovarian hormones may have a protective effect on the cardiovascular system. We evaluated the effects of ovariectomy and/or estradiol on sympathovagal balance and heart rate variability (HRV) in female spontaneously hypertensive rats (SHR) with tachycardia and compared them to Wistar rats (12 weeks old; N = 8-12). Ovariectomy (OVX) and/or estradiol (10 µg/kg) did not affect basal arterial pressure in either rat strain, but estradiol increased basal heart rate (HR) in OVX SHR (454 ± 18 vs 377 ± 9 bpm). HR changes elicited by methylatropine and propranolol were used to evaluate the sympathovagal balance. Ovariectomy did not affect the cardiac sympathovagal balance of any group, while estradiol increased sympathetic tone in OVX SHR (120 ± 8 vs 56 ± 10 bpm) and sham-operated Wistar rats (57 ± 7 vs 28 ± 4 bpm), and decreased the parasympathetic tone only in OVX SHR (26 ± 7 vs 37 ± 5 bpm). HRV was studied in the frequency domain (Fast Fourier Transformation). Spectra of HR series were examined at low frequency (LF: 0.2-0.75 Hz) and high frequency (HF: 0.75-3 Hz) bands. The power of LF, as well as the LF/HF ratio, was not affected by ovariectomy, but estradiol increased both LF (29 ± 4 vs 18 ± 3 nu in Wistar sham-operated, 26 ± 5 vs 15 ± 3 nu in Wistar OVX, 50 ± 3 vs 38 ± 4 nu in SHR sham-operated, and 51 ± 3 vs 42 ± 3 nu in SHR OVX) and LF/HF (0.48 ± 0.08 vs 0.23 ± 0.03 nu in Wistar sham-operated, 0.41 ± 0.14 vs 0.19 ± 0.05 nu in Wistar OVX, 0.98 ± 0.11 vs 0.63 ± 0.11 nu in SHR sham-operated, and 1.10 ± 0.11 vs 0.78 ± 0.1 nu in SHR OVX). Thus, we suggest that ovariectomy did not affect the cardiac sympathovagal balance of SHR or Wistar rats, while estradiol increased the sympathetic modulation of HR.
绝经前女性心血管疾病（包括高血压）的发病率较低，这导致人们得出结论，卵巢激素可能对心血管系统具有保护作用。我们评估了卵巢切除术和/或雌二醇对伴心动过速的自发性高血压大鼠（SHR）的交感神经-迷走神经平衡和心率变异性（HRV）的影响，并将其与 Wistar 大鼠进行了比较（12 周龄；N=8-12）。卵巢切除术（OVX）和/或雌二醇（10µg/kg）对两种大鼠的基础动脉压均无影响，但雌二醇增加了 OVX SHR 的基础心率（HR）（454±18 比 377±9 bpm）。用甲基阿托品和普萘洛尔引起的 HR 变化来评估交感神经-迷走神经平衡。卵巢切除术对任何组的心脏交感神经-迷走神经平衡均无影响，而雌二醇增加了 OVX SHR 的交感神经张力（120±8 比 56±10 bpm）和假手术 Wistar 大鼠（57±7 比 28±4 bpm），并降低了仅 OVX SHR 的副交感神经张力（26±7 比 37±5 bpm）。HRV 在频域（快速傅立叶变换）中进行了研究。在低频（LF：0.2-0.75 Hz）和高频（HF：0.75-3 Hz）带宽下检查 HR 系列的频谱。LF 的功率以及 LF/HF 比值不受卵巢切除术的影响，但雌二醇增加了 LF（Wistar 假手术组 29±4 比 18±3 nu，Wistar OVX 组 26±5 比 15±3 nu，SHR 假手术组 50±3 比 38±4 nu，SHR OVX 组 51±3 比 42±3 nu）和 LF/HF（Wistar 假手术组 0.48±0.08 比 0.23±0.03 nu，Wistar OVX 组 0.41±0.14 比 0.19±0.05 nu，SHR 假手术组 0.98±0.11 比 0.63±0.11 nu，SHR OVX 组 1.10±0.11 比 0.78±0.1 nu）。因此，我们认为卵巢切除术并未影响 SHR 或 Wistar 大鼠的心脏交感神经-迷走神经平衡，而雌二醇增加了 HR 的交感神经调节。
