Schnur P, Martinez Y, Hang D
Department of Psychology, University of Southern Colorado, Pueblo 81001.
Behav Neurosci. 1988 Apr;102(2):254-9. doi: 10.1037//0735-7044.102.2.254.
Two experiments were conducted to investigate the effects of stress on morphine-elicited locomotor activity in hamsters. In Experiment 1, half of the animals were habituated to handling and injection procedures (low-stress condition) and half were not (high-stress condition) prior to 6 days of testing with a low dose (2.5 mg/kg) of morphine. On the first test day, morphine elicited hyperactivity among habituated animals, whereas among nonhabituated animals morphine elicited hypoactivity. The effects of handling diminished across test days, so that on the last test day, morphine elicited hyperactivity in both habituated and nonhabituated animals. In Experiment 2, the effect of a noise stressor on activity elicited by three doses of morphine (2.5, 5.0, and 15 mg/kg) was investigated. Half of the animals were tested under conditions of low noise stress (70 dB), and half were tested under conditions of high noise stress (90 dB). Results indicated that the effects of each dose of morphine were potentiated in the high-stress relative to the low-stress condition. Both experiments demonstrated that environmental stressors can potentiate the response to exogenous opiate administration in hamsters. Moreover, the results are consistent with the hypothesis that stress induces the release of endogenous opioids which summate with exogenous opiates to determine the final effective dose.
进行了两项实验来研究应激对仓鼠吗啡诱导的运动活动的影响。在实验1中，在使用低剂量（2.5毫克/千克）吗啡进行6天测试之前，一半的动物习惯了处理和注射程序（低应激条件），另一半则没有（高应激条件）。在第一个测试日，吗啡在习惯化动物中引起多动，而在未习惯化动物中引起少动。处理的影响在测试日中逐渐减弱，因此在最后一个测试日，吗啡在习惯化和未习惯化动物中均引起多动。在实验2中，研究了噪声应激源对三种剂量吗啡（2.5、5.0和15毫克/千克）诱导的活动的影响。一半的动物在低噪声应激（70分贝）条件下进行测试，另一半在高噪声应激（90分贝）条件下进行测试。结果表明，相对于低应激条件，每种剂量的吗啡在高应激条件下的作用都增强了。两项实验均表明，环境应激源可增强仓鼠对外源阿片类药物给药的反应。此外，结果与应激诱导内源性阿片类物质释放的假设一致，内源性阿片类物质与外源性阿片类药物相加以确定最终有效剂量。
