Hebert T J, Cashion M F, Dohanich G P
Department of Psychology, Tulane University, New Orleans, LA 70118.
Physiol Behav. 1994 Nov;56(5):835-9. doi: 10.1016/0031-9384(94)90312-3.
The muscarinic receptor blocker, scopolamine, inhibits the display of lordosis behavior in female rats but its effectiveness depends on hormonal conditions. In these experiments, systemic administration of scopolamine (0.031-4 mg/kg) inhibited lordosis in ovariectomized rats brought into receptivity by treatment with a low dose of estradiol benzoate (EB, 0.25 micrograms for 3 days) with progesterone (P, 500 micrograms for 1 day), or a high dose of EB (25 micrograms for 3 days) with and without P. However, the effectiveness of scopolamine was reduced at the high dose of EB and with the addition of P. Furthermore, scopolamine failed to inhibit lordosis in females treated on a second week with the high dose of EB with or without P, unless an interval of at least 3 weeks separated the two sets of steroid treatments. The reduced effectiveness of scopolamine cannot be explained by peripheral mechanisms because its inhibitory effect on lordosis also was reduced following repeated hormonal exposure even when scopolamine was infused directly into the lateral ventricles.
毒蕈碱受体阻断剂东莨菪碱可抑制雌性大鼠的脊柱前凸行为，但其效果取决于激素状况。在这些实验中，全身给予东莨菪碱（0.031 - 4毫克/千克）可抑制经低剂量苯甲酸雌二醇（EB，0.25微克，连续3天）和孕酮（P，500微克，1天）处理或高剂量EB（25微克，连续3天）处理（无论有无P）后进入发情期的去卵巢大鼠的脊柱前凸行为。然而，在高剂量EB且添加P的情况下，东莨菪碱的效果会降低。此外，东莨菪碱无法抑制在第二周接受高剂量EB处理（无论有无P）的雌性大鼠的脊柱前凸行为，除非两组类固醇处理之间间隔至少3周。东莨菪碱效果降低无法用外周机制解释，因为即使将东莨菪碱直接注入侧脑室，在反复激素暴露后其对脊柱前凸的抑制作用也会降低。
