Lagamma E F, Itskovitz J, Rudolph A M
Pediatr Res. 1983 Feb;17(2):162-7. doi: 10.1203/00006450-198302000-00016.
The cardiovascular and respiratory effects of the naturally occurring endogenous opiate, methionine-enkephalin, were studied in 23 fetal sheep, five newborn lambs, 15 pregnant sheep, and four nonpregnant ewes. The opiate peptide produced dose-dependent decreases in heart rate and blood pressure in fetal and neonatal lambs but increased heart rate and blood pressure followed immediately by decreased heart rate and blood pressure in pregnant ewes. The circulatory responses were examined by pharmacologic blockade of receptor activity and by vagotomy. The bradycardia and hypotension in the fetus and tachycardia and hypertension in the adult were shown to be mediated by autonomic efferent nerves. Sinoaortic denervation did not affect the fetal responses to infused enkephalin. Respiration decreased in fetal as well as postnatal animals even at doses of methionine-enkephalin that did not significantly affect heart rate and blood pressure. These data indicate that the cardiovascular effects of infused enkephalins undergo maturational changes and are mediated by the autonomic nervous system.
在23只胎羊、5只新生羔羊、15只妊娠母羊和4只未妊娠母羊中研究了天然存在的内源性阿片肽甲硫氨酸脑啡肽对心血管和呼吸系统的影响。阿片肽在胎羊和新生羔羊中产生剂量依赖性的心率和血压降低，但在妊娠母羊中增加心率和血压，随后立即出现心率和血压下降。通过药理学阻断受体活性和迷走神经切断术来检查循环反应。结果表明，胎儿的心动过缓和低血压以及成年动物的心动过速和高血压是由自主传出神经介导的。窦主动脉去神经支配并不影响胎儿对注入脑啡肽的反应。即使在甲硫氨酸脑啡肽剂量未显著影响心率和血压的情况下，胎儿和出生后动物的呼吸也会减少。这些数据表明，注入脑啡肽的心血管效应会发生成熟变化，并由自主神经系统介导。
