Rosenkranz J A, Grace A A
Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
J Neurosci. 1999 Dec 15;19(24):11027-39. doi: 10.1523/JNEUROSCI.19-24-11027.1999.
The basolateral amygdala (BLA) is implicated in responding to affective stimuli. Dopamine (DA) is released in the BLA during numerous conditions; however, the neurophysiological effects of DA in the BLA have not been examined in depth. In this study, the effects of DA receptor manipulation on spontaneous and afferent-driven neuronal firing were examined using in vivo extracellular single-unit recordings in parallel with systemic and iontophoretic drug application, and stimulation of the substantia nigra/ventral tegmental area in the rat. The effects of DA receptor activation in the BLA were found to depend on the characteristics of the BLA neuron examined, causing an increase in the firing rate of putative interneurons and a decrease in the firing of identified projection neurons. Additionally, DA receptor activation attenuated short-latency spikes evoked by electrical stimulation of prefrontal cortical and mediodorsal thalamic inputs to the BLA while potentiating the responses evoked by electrical stimulation of sensory association cortex. DA receptor activation can thus attenuate BLA projection neuron firing via two mechanisms: (1) by a direct inhibition, and (2) by indirect actions mediated via activation of BLA interneurons. This is hypothesized to lead to a global filtration of weaker inputs. Moreover, DA potentiates sensory inputs and attenuates medial prefrontal cortex inputs to the BLA. Conditions in which DA is released in the BLA, such as during the presentation of an affective stimulus, will lead to a potentiation of the strongest sensory input and a dampening of cortical inhibition over the BLA, thus augmenting the response to affective sensory stimuli.
基底外侧杏仁核（BLA）参与对情感刺激的反应。在多种情况下，多巴胺（DA）会在BLA中释放；然而，DA在BLA中的神经生理作用尚未得到深入研究。在本研究中，通过体内细胞外单单位记录，结合全身和离子电渗药物应用，以及对大鼠黑质/腹侧被盖区的刺激，研究了DA受体操纵对自发和传入驱动神经元放电的影响。发现DA受体激活在BLA中的作用取决于所检查的BLA神经元的特性，导致假定的中间神经元放电率增加，而已识别的投射神经元放电减少。此外，DA受体激活减弱了前额叶皮质和丘脑背内侧核输入到BLA的电刺激所诱发的短潜伏期尖峰，同时增强了感觉联合皮质电刺激所诱发的反应。因此，DA受体激活可通过两种机制减弱BLA投射神经元的放电：（1）通过直接抑制，以及（2）通过激活BLA中间神经元介导的间接作用。据推测，这会导致对较弱输入的整体过滤。此外，DA增强了感觉输入，并减弱了内侧前额叶皮质对BLA的输入。DA在BLA中释放的情况，例如在呈现情感刺激期间，将导致最强感觉输入的增强以及皮质对BLA抑制的减弱，从而增强对情感感觉刺激的反应。
