Díaz-Véliz G, Benavides M S, Butrón S, Dussaubat N, Mora S
Programa de Farmacología Molecular y Clínica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
Pharmacol Biochem Behav. 1999 Jan;62(1):21-9. doi: 10.1016/s0091-3057(98)00097-5.
The influence of the hormonal condition on the reactivity of central dopamine (DA) receptors was studied in male and in intact and ovariectomized (OVX) female rats. They were injected with selective DA agonists, acting either on D1 (SKF 38393, 2.5 or 10 mg/kg) or D2 receptors (PPHT, 31.3 or 125 microg/kg), or with selective DA antagonists, acting either on D1 (SCH 23390, 6.25 or 25 microg/kg), or D2 receptors (sulpiride, 10 or 40 mg/kg). The acquisition of an avoidance conditioning response (CAR) and the performance of some spontaneous motor behaviors were tested. Both D1 and D2 agonists and antagonists impaired the acquisition of CARs in diestrous, OVX, and male rats. Nevertheless, the effects of these drugs during estrus and in estradiol-primed OVX rats were different according to the drug and the dose injected. Whereas SKF 38393 failed to induce significative changes, PPHT and low doses of SCH 23390 and sulpiride improved the acquisition of CARS in those groups. The effects on conditioning were not accompanied with equivalent changes in spontaneous motor activity. Estradiol level fluctuations that occur in female rats within the estrous cycle or in OVX rats primed with estradiol would be responsive of changes in the response to DA agents. Although the reactivity of central DA systems is differentially affected by the hormonal condition of the rat, the precise mechanism of this modulatory action remains unknown.
在雄性以及完整和去卵巢（OVX）雌性大鼠中研究了激素状态对中枢多巴胺（DA）受体反应性的影响。给它们注射选择性DA激动剂，作用于D1（SKF 38393，2.5或10mg/kg）或D2受体（PPHT，31.3或125μg/kg），或注射选择性DA拮抗剂，作用于D1（SCH 23390，6.25或25μg/kg）或D2受体（舒必利，10或40mg/kg）。测试了回避条件反射反应（CAR）的获得以及一些自发运动行为的表现。D1和D2激动剂及拮抗剂均损害了动情间期、去卵巢大鼠和雄性大鼠中CAR的获得。然而，根据药物和注射剂量的不同，这些药物在发情期以及用雌二醇预处理的去卵巢大鼠中的作用有所不同。虽然SKF 38393未能引起显著变化，但PPHT以及低剂量的SCH 23390和舒必利改善了这些组中CAR的获得。对条件反射的影响并未伴随着自发运动活动的同等变化。雌性大鼠发情周期内或用雌二醇预处理的去卵巢大鼠中发生的雌二醇水平波动可能与对DA药物反应的变化有关。尽管大鼠的激素状态对中枢DA系统的反应性有不同影响，但这种调节作用的确切机制仍不清楚。
