Cheng P Y, Decena J A, Wu D L, Cheng Y, Szeto H H
Department of Pharmacology, Cornell University Medical College, New York, New York 10021.
Pediatr Res. 1991 Aug;30(2):202-6. doi: 10.1203/00006450-199108000-00015.
The effects of naloxone and naloxonazine (an irreversible mu1 antagonist) administration on fetal breathing movement (FBM) patterns under control, physiologic conditions were studied in 10 fetal lambs with chronically implanted electromyogram electrodes in the diaphragm. Neither naloxone (6 mg/h) nor naloxonazine (34 mg) had any effect on the total number of diaphragmatic electromyogram bursts per hour, mean instantaneous breathing rate, or incidence of breathing. However, naloxonazine caused a more fragmented FBM pattern, as indicated by a significant increase in both the number of apneas and pauses per hour, along with decreased epoch duration. In addition, naloxonazine caused a significant reduction in the stability or regularity of the breathing rate. Naloxone had no effects on the dynamic pattern of the FBM. These results suggest that endogenous opiate peptides play a tonic role at the mu1, receptor to maintain both the continuity and stability of the FBM pattern in late gestation.
在10只通过在膈肌长期植入肌电图电极的胎羊中，研究了在对照生理条件下给予纳洛酮和纳洛嗪（一种不可逆的μ1拮抗剂）对胎儿呼吸运动（FBM）模式的影响。纳洛酮（6毫克/小时）和纳洛嗪（34毫克）均未对每小时膈肌肌电图爆发的总数、平均瞬时呼吸频率或呼吸发生率产生任何影响。然而，纳洛嗪导致FBM模式更加碎片化，表现为每小时呼吸暂停和停顿的次数显著增加，同时发作持续时间缩短。此外，纳洛嗪导致呼吸频率的稳定性或规律性显著降低。纳洛酮对FBM的动态模式没有影响。这些结果表明，内源性阿片肽在μ1受体上发挥着紧张性作用，以维持妊娠后期FBM模式的连续性和稳定性。
