Center for the Study of Emotion and Attention

描述(申请人提供)：我们在恐惧强化惊吓测试中发现，将吗啡局部注射到杏仁内侧核(Me)完全阻断条件性恐惧的表达，而将类似剂量的吗啡注入中央(Ce)、基底外侧(Bla)或尾壳核(Ce)则没有效果。向Me内注入吗啡的作用可通过向Me内联合注入纳洛酮而完全逆转。此外，局部注射纳洛酮完全阻止了全身注射的吗啡阻止恐惧加剧的惊吓。局部输注Mu或Delta选择性阿片激动剂的效果与吗啡相似。目前尚不清楚为什么局部向Me注入吗啡能如此有效地阻断恐惧增强惊恐，因为我们还没有发现损伤的Me阻断恐惧增强惊吓。尽管有报道称ME向CE投射，但我们认为这种明显的投影可能是示踪剂扩散到CE的结果，因为我们没有发现将敏感的顺行示踪剂生物素化葡聚糖离散地注入ME内从ME到CE的投射。相反，ME大量投射到终纹前内侧床核(BNSTam)、后中间BNSTpi和下丘脑腹内侧核(VMH)。因为BNST大量投射到Ce，实际上从Me到BNST再到Ce的Ce投射的输出部分最多，因此很可能参与了吗啡与Me受体结合而激活的抑制回路。或者，其他大脑区域也可能参与这一假定的恐惧抑制回路。为了评估这一点，我们将吗啡注入ME，然后使用免疫细胞化学Fos蛋白作为神经元激活的标志来分析大脑。ME内局部注射吗啡后，Me、BNST腹侧外侧隔核及邻近区域Fos表达增加，Ce与Bla交界处的间质细胞团增多，腹侧下托Fos表达增加。因为这些区域中的一些与抑制恐惧有关，我们认为我们可能已经进入了参与抑制恐惧的神经网络。因此，我们将系统地研究BNST、腹侧下丘脑、外侧隔核、下丘脑腹内侧核和夹层细胞在吗啡局部给药抗焦虑作用中的作用，以及吗啡、丁螺环酮和安定的抗焦虑作用。我们还将评估阿片受体在Me、Bla的神经肽Y(NPY)细胞和Bla的GABA以及上述不同脑区在恐惧增强的消退和条件性抑制中的作用。最后，我们将在11T磁铁上对麻醉大鼠进行气味介导的恐惧保持、消退和条件性抑制的脑成像，并测量血压

DESCRIPTION (provided by applicant): We have found in the fear potentiated startle test that bilateral local infusion of morphine into the medial nucleus of the amygdala (Me) completely blocks the expression of conditioned fear whereas infusion of comparable doses into the central (Ce), basolateral (Bla) or caudate-putamen had no effect. The effects of morphine infused into the Me were completely reversed by co-infusion of naloxone into the Me. Moreover, local infusion of naloxone into the Me completely prevented morphine, given systemically, from blocking fear potentiated startle. Local infusion of mu or delta selective opiate agonists had similar effects to morphine. At the present time it is not clear why local infusion of morphine into the Me so effectively blocks fear potentiated startle because we have not found that lesions of the Me block fear potentiated startle. Although the Me has been reported to project to the Ce we believe this apparent projection probably resulted from spread of the tracer into the Ce, because we have not found projections from the Me to the Ce using discrete infusion of the sensitive anterograde tracer biotinylated dextran into the Me. Instead, the Me projects heavily to anteriomedial bed nucleus of the stria terminalis (BNSTam) the posterior intermediate BNSTpi), and the ventromedial hypothalamus (VMH). Because the BNST projects heavily to the Ce, in fact most heavily to the output division of the Ce projections from the Me to the BNST and then to the Ce could well be involved in an inhibitory circuit activated by morphine binding to receptors in the Me. Alternatively, other brain areas might also participate in this putative fearinhibition circuit. To evaluate this, we infused morphine into the Me and then analyzed the brain using immunocytochemistry for Fos protein as a marker of neuronal activation. Local infusion of morphine into the ME led to increases in Fos in the Me, ventral lateral septal nucleus and adjacent areas of the BNST, the intercalated cell mass on the border between the Ce and Bla, and the ventral subiculum. Because some of these areas have been implicated in the inhibition of fear we believe we may have tapped into a neuronal network involved in the inhibition of fear. Hence, we will determine the role of the BNST, ventral subiculum, lateral septum, ventromedial hypothalamus and intercalated cells in the anxiolytic effects of morphine given locally into the Me, as well as the anxiolytic effects of morphine, buspirone and diazepam given systemically. We wll also evaluate the role of opiate receptors in the Me, neuropeptide Y (NPY) cells in the Bla and GABA in the Bla, as well as various brain areas identified above, in extinction and conditioned inhibition of fear potentiated startle. Finally, we will carry out brain imaging of odor-mediated fear retention, extinction, and conditioned inhibition in anesthetized rats usingfMRI in an 11 T magnet measured with blood pressure