Natali Luiz Henrique, Troiano Jéssica Antonini, Potje Simone Regina, Dias Daniel Penteado Martins, Antoniali Cristina
Multicenter Graduate Program in Physiological Sciences, SBFis, Brazil; Department of Basic Sciences, School of Dentistry of Araçatuba, São Paulo State University - UNESP, Araçatuba, São Paulo, Brazil.
Multicenter Graduate Program in Physiological Sciences, SBFis, Brazil; Department of Basic Sciences, School of Dentistry of Araçatuba, São Paulo State University - UNESP, Araçatuba, São Paulo, Brazil; Curso de Medicina, Faculdades de Dracena, Fundação Dracenense de Educação e Cultura - UNIFADRA, Dracena, São Paulo, Brazil.
Pregnancy Hypertens. 2022 Jun;28:180-188. doi: 10.1016/j.preghy.2022.05.002. Epub 2022 May 10.
Hypertension is associated to impaired baroreflex sensitivity (BRS). In spontaneously hypertensive rats (SHR), pregnancy reduces blood pressure, and this effect has been associated to increase nitric oxide (NO) bioavailability. Increased NO bioavailability has been linked to improve BRS in hypertensive animals. Therefore, we hypothesize that pregnancy improves the BRS in SHR. We performed experiments to evaluate the vasomotor and cardiac autonomic modulation, also to evaluate the BRS at baseline conditions (spontaneous) and after phenylephrine (PE) and sodium nitroprusside (SNP) administrations in non-pregnant (NP) and pregnant (P) Wistar rats and SHR. Beat-to-beat time series with systolic arterial pressure values were generated and processed by Fast Fourier Transform (spectral analysis). Next, spectra were integrated into low-frequency (LF) band and had their power taken as an index of sympathetic modulation on arterial pressure. Reduced mean arterial pressure was observed in P-groups when compared to NP matched rats, although we did not observe alterations in heart rate (HR). In SHR-NP, spectral analysis revealed altered cardiovascular autonomic modulation when compared to the other groups. However, in SHR-P the autonomic parameters were similar to those observed in Wistar-NP, suggesting that pregnancy changed autonomic modulation. BRS assessed by means of the sequence method was found similar in P-groups. Pregnancy reduced the BRS during hypotension in Wistar. BRS assessed with PE and SNP administration was found lower in SHR-NP as compared to Wistar-NP, and it was not altered by pregnancy. In conclusion, pregnancy did not improve the BRS in SHR, but normalized altered sympathetic vasomotor modulation in SHR.
高血压与压力反射敏感性（BRS）受损有关。在自发性高血压大鼠（SHR）中，妊娠可降低血压，且这种效应与一氧化氮（NO）生物利用度增加有关。NO生物利用度增加与高血压动物的BRS改善有关。因此，我们推测妊娠可改善SHR的BRS。我们进行了实验，以评估血管运动和心脏自主神经调节，同时评估非妊娠（NP）和妊娠（P）的Wistar大鼠及SHR在基线条件下（自发状态）以及给予去氧肾上腺素（PE）和硝普钠（SNP）后的BRS。通过快速傅里叶变换（频谱分析）生成并处理包含收缩期动脉压值的逐搏时间序列。接下来，将频谱整合到低频（LF）波段，并将其功率作为动脉压交感神经调节的指标。与NP匹配的大鼠相比，P组的平均动脉压降低，尽管我们未观察到心率（HR）的改变。在SHR-NP中，与其他组相比，频谱分析显示心血管自主神经调节发生了改变。然而，在SHR-P中，自主神经参数与Wistar-NP中观察到的相似，表明妊娠改变了自主神经调节。通过序列法评估的P组BRS相似。妊娠降低了Wistar大鼠低血压期间的BRS。与Wistar-NP相比，SHR-NP中给予PE和SNP后评估的BRS较低，且妊娠未改变该指标。总之，妊娠并未改善SHR的BRS，但使SHR中改变的交感神经血管运动调节恢复正常。
