Alotaibi Mohammed F
Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
Reprod Sci. 2020 Apr;27(4):1024-1029. doi: 10.1007/s43032-019-00104-6. Epub 2020 Jan 1.
Continuous oxytocin exposure to augment labor contractions may cause receptor desensitization and further reduce the uterine response to oxytocin, resulting in an increased risk of uterine atony. This study aimed to investigate and compare the uterine response to continuous and intermittent oxytocin stimulation. We hypothesized that intermittent brief episodes of oxytocin separated by recovery periods rather than continuous oxytocin application improves subsequent uterine contractions. Myometrial strips were isolated from term-pregnant rats (22 days of gestation; n = 11), mounted in tissue bath chambers, and exposed to continuous oxytocin (5 nM) for 2 h or 6 repeated episodes of 10-min oxytocin exposure (5 nM) separated by 10 min of recovery period in Krebs solution. Contractile parameters (force amplitude, frequency, and integral force) significantly decreased during continuous oxytocin exposure compared with control (n = 11; P < 0.01). Interestingly, myometrial contractility significantly increased during subsequent short intermittent oxytocin exposure which was sustained for 6 h compared with control or continuous exposure (n = 11; P < 0.01). Brief intermittent oxytocin stimulations resulted in better uterine response and improved contractile force than continuous exposure, which may be attributed to attenuation of receptor desensitization or recovery of oxytocin receptor function following intermittent exposure. These findings would help maintain adequate strong contractions to avoid postpartum bleeding.
持续使用缩宫素增强宫缩可能会导致受体脱敏，并进一步降低子宫对缩宫素的反应，从而增加子宫收缩乏力的风险。本研究旨在调查和比较子宫对持续和间歇性缩宫素刺激的反应。我们假设，与持续应用缩宫素相比，在恢复期间隔进行间歇性短暂缩宫素刺激可改善随后的子宫收缩。从足月妊娠大鼠（妊娠22天；n = 11）分离出子宫肌条，安装在组织浴槽中，使其暴露于持续缩宫素（5 nM）2小时，或在Krebs溶液中恢复10分钟后，进行6次重复的10分钟缩宫素暴露（5 nM）。与对照组（n = 11；P < 0.01）相比，持续缩宫素暴露期间收缩参数（力幅度、频率和积分力）显著降低。有趣的是，与对照组或持续暴露相比，在随后持续6小时的短暂间歇性缩宫素暴露期间，子宫肌层收缩力显著增加（n = 11；P < 0.01）。短暂间歇性缩宫素刺激比持续暴露导致更好的子宫反应和更强的收缩力，这可能归因于间歇性暴露后受体脱敏的减弱或缩宫素受体功能的恢复。这些发现将有助于维持足够强的宫缩以避免产后出血。
