Vernotica E M, Morrell J I
Behavioral Pharmacology Research Unit, Johns Hopkins School of Medicine, Baltimore, MD 21224, USA.
Physiol Behav. 1998 Jun 1;64(3):399-407. doi: 10.1016/s0031-9384(98)00092-4.
We have determined the temporal pattern of plasma cocaine levels and increased activity that result from acute systemic injections of cocaine to female rats in two different endocrine and behavioral states, in nonmaternal virgins and in lactating maternal dams. Plasma levels of cocaine as well as ambulatory and rearing activity were determined every 30 min for a total of 300 min after subcutaneous injections of either 10, 20, or 40 mg/kg of cocaine. Virgin females had no prior drug history, whereas lactating, maternal dams had received two cocaine injections before activity testing. Within 30 min after an injection, cocaine in the plasma and activity were substantially elevated, and generally remained so for 270-300 min. Overall, plasma cocaine levels and activity were well correlated and followed a predictable dose-response pattern. The onset, peak, duration, and decline of activity corresponded generally to the onset, peak, duration, and decline of plasma cocaine. For virgins, mean ambulatory activity increased 2.5-4.0-fold over baseline, whereas in lactating females activity increased 5-11-fold over baseline. Stereotypy did not occur. Although the general responsivity of these females to cocaine was very similar to that reported for males, there are differences in the timing of peak activity and the return of activity to baseline when the virgins and the lactating dams are compared to each other and to reports by others on male rats. These data support the hypothesis that endocrine or behavioral state may influence the responsiveness of animals to cocaine.
我们已经确定了在两种不同内分泌和行为状态下，即未生育的处女雌鼠和正在哺乳的母鼠中，急性全身注射可卡因后血浆可卡因水平和活动增加的时间模式。在皮下注射10、20或40mg/kg可卡因后，每30分钟测定一次血浆可卡因水平以及走动和竖毛活动，共持续300分钟。处女雌鼠没有用药史，而正在哺乳的母鼠在活动测试前接受过两次可卡因注射。注射后30分钟内，血浆中的可卡因和活动显著升高，并且通常在270 - 300分钟内保持这种状态。总体而言，血浆可卡因水平和活动具有良好的相关性，并遵循可预测的剂量反应模式。活动的起始、峰值、持续时间和下降通常与血浆可卡因的起始、峰值、持续时间和下降相对应。对于处女雌鼠，平均走动活动比基线增加了2.5 - 4.0倍，而在哺乳雌鼠中，活动比基线增加了5 - 11倍。没有出现刻板行为。尽管这些雌鼠对可卡因的总体反应性与报道的雄鼠非常相似，但当将处女雌鼠和哺乳母鼠相互比较以及与其他关于雄鼠的报道进行比较时，在活动峰值时间和活动恢复到基线的时间方面存在差异。这些数据支持了内分泌或行为状态可能影响动物对可卡因反应性的假设。
