Syutkina E V
Institute of Paediatrics of AMS of USSR, Laboratory of Experimental Pathology of the Brain, Moscow.
Gynecol Obstet Invest. 1988;25(4):249-57. doi: 10.1159/000293794.
The effect of parasympathetic (with atropine) and beta-adrenergic (with propranolol) blockade on fetal heart rate variability (HRV) was studied in 162 term fetal Wistar rats. Administration of 1.3 mg of atropine into the jugular vein of the female rat led to an identical decrease of the RR interval in adult rats and in fetuses (about 10%). Administration of 2 mg of propranolol caused a rise in the RR interval by 19% in rats and by 7-9% in fetuses. Overall HRV indices (RMSM, CV) decrease was more pronounced in adult rats than in fetuses. Upon simultaneous administration of both blocking agents the RR interval in adult rats did not differ from the control values; in fetuses it was reduced by 6%. In adult rats HRV indices decreased considerably (by 70%) and their values were within the limits of the estimation error; in fetuses, HRV indices were no higher than upon the administration of any of the blocking agents. Umbilical cord clamping caused a decrease of PO2 in brain tissue from 24.7 +/- 1.7 to 4.7 +/- 0.8 mm Hg within 15 min and led to an immediate increase of the RR interval and the HRV indices if blocking agents were not used. The administration of one or both blocking agents abolished the initial (during the first 7 min of asphyxia) increase of RMSM and CV. Thus, HRV in fetal rats depends to a great extent on the activity of the autonomic nervous system, though it is not fully determined by it. Acute asphyxia causes stimulation of the autonomic nervous system leading to fetal distress.
在162只足月的Wistar胎鼠中研究了副交感神经（加用阿托品）和β-肾上腺素能（加用普萘洛尔）阻断对胎心率变异性（HRV）的影响。向雌性大鼠颈静脉注射1.3mg阿托品后，成年大鼠和胎鼠的RR间期均出现相同程度的降低（约10%）。注射2mg普萘洛尔后，大鼠的RR间期增加19%，胎鼠增加7 - 9%。总体而言，成年大鼠HRV指标（均方根连续差值、变异系数）的降低比胎鼠更明显。同时给予两种阻断剂后，成年大鼠的RR间期与对照值无差异；胎鼠的RR间期降低了6%。成年大鼠的HRV指标显著降低（70%），其值在估计误差范围内；胎鼠的HRV指标不高于单独给予任何一种阻断剂时的水平。脐带夹闭后15分钟内，脑组织中的PO2从24.7±1.7降至4.7±0.8mmHg，若未使用阻断剂，则会导致RR间期和HRV指标立即增加。给予一种或两种阻断剂可消除窒息最初7分钟内均方根连续差值和变异系数的升高。因此，胎鼠的HRV在很大程度上依赖于自主神经系统的活动，尽管并非完全由其决定。急性窒息会刺激自主神经系统，导致胎儿窘迫。
