Mu Ping, Fuchs Thomas, Saal Daniel B, Sorg Barbara A, Dong Yan, Panksepp Jaak
Program in Neuroscience, Department of VCAPP, Washington State University, Pullman, WA 99164, United States.
Neurosci Lett. 2009 Mar 27;453(1):31-5. doi: 10.1016/j.neulet.2009.02.007. Epub 2009 Feb 10.
Ultrasonic vocalization at 55kHz (55kHz-USVs) by rodents has been proposed to be a behavioral manifestation of affectively positive incentive motivation. To examine the extent to which 55kHz-USV emissions correlate with cocaine-induced locomotor activity, we measured cocaine-induced 55kHz-USVs and their relationship to cocaine-induced locomotor sensitization in rats. We demonstrate that similar to locomotor responses, 55kHz-USVs are also sensitized by exposure to cocaine. Furthermore, we show that the magnitude of cocaine-induced 55kHz-USV sensitization is positively correlated with that of locomotor sensitization. Moreover, we demonstrate that rats selectively bred for high rates of 55kHz-USVs exhibit higher levels of cocaine-induced 55kHz-USV sensitization than animals selectively bred for low levels of 55kHz USVs. These results suggest that the neural circuits underlying 55kHz-USV, which may directly reflect affective experience/motivation, can be sensitized by cocaine in a way that resembles locomotor sensitization.
啮齿动物发出的55千赫兹超声波发声（55kHz-USVs）被认为是情感上积极激励动机的一种行为表现。为了研究55kHz-USV发射与可卡因诱导的运动活动之间的关联程度，我们测量了可卡因诱导的大鼠55kHz-USVs及其与可卡因诱导的运动敏化的关系。我们证明，与运动反应类似，55kHz-USVs也会因接触可卡因而敏化。此外，我们表明可卡因诱导的55kHz-USV敏化程度与运动敏化程度呈正相关。而且，我们证明，经过选择性培育以产生高频率55kHz-USVs的大鼠比经过选择性培育以产生低水平55kHz-USVs的动物表现出更高水平的可卡因诱导的55kHz-USV敏化。这些结果表明，55kHz-USV背后的神经回路可能直接反映情感体验/动机，它可以被可卡因以类似于运动敏化的方式敏化。
