Activity of muscle sympathetic neurons during normotensive pregnancy.
Activity of muscle sympathetic neurons during normotensive pregnancy.
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正常血压妊娠期间肌肉交感神经元的活动。
DOI：
10.1152/ajpregu.00121.2016
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Steinback,CraigD
中科院分区：
文献类型：
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作者：
Schmidt,SydneyML;Usselman,CharlotteW;Martinek,Eric;Stickland,MichaelK;Julian,ColleenG;Chari,Radha;Khurana,Rshmi;Davidge,SandraT;Davenport,MargieH;Steinback,CraigD
在病理群体中，交感神经活性升高与单个交感神经元的活性增加相关。我们使用自定义动作电位检测软件分析了18名正常妊娠妇女（妊娠晚期; 33 ± 5周）和19名非妊娠妇女在休息时和一个子集（分别为10和13）在冷加压挑战期间的多单位交感神经活动。虽然每个爆发的动作电位数量和基于活跃振幅的“簇”数量在组间没有差异，但孕妇在休息时每分钟的交感神经动作电位总数较高。单个簇在每次爆发中主要活跃一次，这表明它们代表单个神经元。静息状态下，正常妊娠组动作电位的连续性（峰间期36 ± 10 ms）较非妊娠组（50 ± 27 ms;P< 0.001）更接近。妊娠妇女的总外周阻力（11.7 ± 3.0 mmHg·l-1·min）低于非妊娠妇女（15.1 ± 2.7 mmHg·l-1·min;P< 0.001），表明神经血管传导减弱。由于R-R间期缩短以及爆发频率增加，冷加压减少了两组中每次爆发的动作电位数量;每分钟总神经放电量不变。因此，在血压正常的妊娠期间交感神经活性升高是多单位爆发发生率增加的特异性因素。这可能是由于突发输出的中央门控减少，而不是中央驱动的普遍增加。这些数据也强化了这样一个概念，即怀孕似乎是我们所知道的慢性交感神经过度活跃的唯一健康状态。
In pathological populations, elevated sympathetic activity is associated with increased activity of individual sympathetic neurons. We used custom action potential detection software to analyze multiunit sympathetic activity in 18 normotensive pregnant women (third trimester; 33 ± 5 wk) and 19 nonpregnant women at rest and a subset (10 and 13, respectively) during a cold pressor challenge. Although the number of action potentials per burst and number of active amplitude-based “clusters” were not different between groups, the total number of sympathetic action potentials per minute was higher in pregnant women at rest. Individual clusters were active predominately once per burst, suggesting they represent single neurons. Action potentials occurred in closer succession in normotensive pregnant (interspike interval 36 ± 10 ms) versus nonpregnant women (50 ± 27 ms;P< 0.001) at rest. Pregnant women had a lower total peripheral resistance (11.7 ± 3.0 mmHg·l−1·min) than nonpregnant women (15.1 ± 2.7 mmHg·l−1·min;P< 0.001), indicating a blunted neurovascular transduction. The cold pressor reduced the number of action potentials per burst in both groups due to shortening of the R-R interval in conjunction with increased burst frequency; total neural firing per minute was unchanged. Thus elevated sympathetic activity during normotensive pregnancy is specific to increased incidence of multiunit bursts. This is likely due to decreased central gating of burst output as opposed to generalized increases in central drive. These data also reinforce the concept that pregnancy appears to be the only healthy state of chronic sympathetic hyperactivity of which we are aware.