The Effects of Nitroglycerin on the Oxytocin Dose-response Profile in Oxytocin-desensitized and Naive Human Myometrium: An In Vitro Study
| Autor: | Gayani S Jayasooriya, Alice Luca, Mrinalini Balki, José Carlos Almeida Carvalho |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Adult
endocrine system medicine.medical_specialty Human myometrium Vasodilator Agents Oxytocin Contractility Nitroglycerin Uterine Contraction 03 medical and health sciences Organ Culture Techniques 0302 clinical medicine Desensitization (telecommunications) Pregnancy 030202 anesthesiology Internal medicine medicine Humans Prospective Studies Dose-Response Relationship Drug Cesarean Section business.industry Area under the curve Oxytocin receptor Confidence interval Drug Combinations Anesthesiology and Pain Medicine Endocrinology Myometrium cardiovascular system Female business 030217 neurology & neurosurgery hormones hormone substitutes and hormone antagonists circulatory and respiratory physiology medicine.drug |
| Zdroj: | Obstetric Anesthesia Digest. 41:120-122 |
| ISSN: | 0275-665X |
| Popis: | Background Nitroglycerin is used for acute reduction in uterine tone. Prolonged oxytocin exposure causes desensitization of oxytocin receptors. It is unknown if nitroglycerin exposure impacts the subsequent action of oxytocin in the setting of oxytocin receptor desensitization. This study investigated the effects of nitroglycerin on oxytocin-desensitized and oxytocin-naive human myometrium and the subsequent response to oxytocin dose-response testing in vitro. Methods Myometrial samples from 17 elective cesarean deliveries were divided into strips and allocated to 1 of 4 groups: (1) oxytocin desensitized and no nitroglycerin; (2) oxytocin desensitized and nitroglycerin; (3) oxytocin naive and nitroglycerin; and (4) oxytocin naive and no nitroglycerin. Final analysis included 28 strips per group. Nitroglycerin groups were exposed to incremental concentrations of nitroglycerin, while no nitroglycerin groups were kept in control (physiological salt) solution. All groups then underwent oxytocin dose-response testing. Primary outcome was motility index (amplitude × frequency; grams × contractions per 10 minutes [g·c/10 min]). Secondary outcomes were amplitude (g), frequency (contractions/10 minutes), and area under the curve (g·s). All outcomes (nitroglycerin and oxytocin dose-response periods) were expressed as a percentage change from baseline. Values were log transformed, compared using regression modeling and reported as the ratio of 2 geometric means (relative difference). Results No significant difference was observed in motility index following nitroglycerin administration in oxytocin-desensitized versus oxytocin-naive groups (relative difference = 19.0%; 95% confidence interval [CI], -32.6 to 109.9; P = .55). On oxytocin dose-response testing, motility index was highest in oxytocin-naive and no nitroglycerin samples (group 4) (1.356 g·c/10 minutes) followed by oxytocin-naive and nitroglycerin (group 3) (0.882 g·c/10 minutes), oxytocin-desensitized and no nitroglycerin (group 1) (0.769 g·c/10 minutes), and oxytocin-desensitized and nitroglycerin (group 2) (0.651 g·c/10 minutes) samples. Motility index was significantly reduced in group 1 vs 4 (relative difference = -43.3%; 95% CI, -66.5 to -4.1; P = .034) and group 2 vs 4 (relative difference = -52.0%; 95% CI, -70.9 to -20.8; P = .004). While in groups 3 vs 4, both amplitude (relative difference = -17.8%; 95% CI, -30.9 to -2.2; P = .27) and area under the curve (AUC; relative difference = -17.5%; 95% CI, -30.7 to -1.8; P = .030) were reduced. Conclusions Nitroglycerin-induced relaxation was not different between oxytocin-desensitized and oxytocin-naive human myometrial strips in vitro. However, oxytocin-induced contractility was attenuated after nitroglycerin exposure in both oxytocin-desensitized and oxytocin-naive samples, with maximum attenuation observed in desensitized tissues. This finding warrants further clinical studies to explore uterine responsiveness to oxytocin in women with oxytocin-augmented labors after nitroglycerin administration. |
| Databáze: | OpenAIRE |
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