Hurd W W, Robertson P A, Riemer R K, Goldfien A, Roberts J M
Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco.
Am J Obstet Gynecol. 1991 Jan;164(1 Pt 1):182-7. doi: 10.1016/0002-9378(91)90651-7.
Cocaine use in pregnancy is associated with a premature labor rate as high as 50%, but little is known about its effect on uterine contractility. To determine whether cocaine directly augments pregnant uterus contractility, uterine strips from 27-day pregnant New Zealand White rabbits (term, 31 days) were exposed to cocaine alone (30 mumol/L) or cocaine plus epinephrine (10(-9) to 10(-5) mol/L) or oxytocin (10(-10) to 10(-6) mol/L). Cocaine alone produced no contractions, but increased the epinephrine sensitivity by 51% and the maximal response by 33%. When beta-adrenoceptors were blocked with DL-propranolol (2 mumol/L), the contractile response to epinephrine was increased, and cocaine's effect was blocked. In the presence of the stereoisomer D-propranolol (2 mumol/L) with no beta-adrenergic antagonist activity, the contractile response to epinephrine was unchanged, but the effect of cocaine was still blocked. We conclude that cocaine directly augments the alpha-adrenergic contractile response of the pregnant rabbit uterus by a mechanism that is blocked by the non-beta-adrenergic effects of propranolol.
孕期使用可卡因与高达50%的早产率相关，但关于其对子宫收缩性的影响却知之甚少。为了确定可卡因是否直接增强妊娠子宫的收缩性，将妊娠27天（足月为31天）的新西兰白兔的子宫条分别单独暴露于可卡因（30 μmol/L）、可卡因加肾上腺素（10⁻⁹至10⁻⁵ mol/L）或催产素（10⁻¹⁰至10⁻⁶ mol/L）中。单独使用可卡因未引起收缩，但使肾上腺素敏感性提高了51%，最大反应提高了33%。当用DL-普萘洛尔（2 μmol/L）阻断β-肾上腺素能受体时，对肾上腺素的收缩反应增强，且可卡因的作用被阻断。在没有β-肾上腺素能拮抗活性的立体异构体D-普萘洛尔（2 μmol/L）存在的情况下，对肾上腺素的收缩反应未改变，但可卡因的作用仍被阻断。我们得出结论，可卡因通过一种被普萘洛尔的非β-肾上腺素能效应阻断的机制直接增强妊娠兔子宫的α-肾上腺素能收缩反应。
