Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, 02447, Republic of Korea.
Department of Biology, Kyung Hee University, Seoul, 02447, Republic of Korea.
Biochem Biophys Res Commun. 2021 Dec 20;584:39-45. doi: 10.1016/j.bbrc.2021.11.014. Epub 2021 Nov 8.
The lateral amygdala (LA) is a main sensory input site from the cortical and thalamic regions. In turn, LA glutamatergic pyramidal neurons strongly project to the basal amygdala (BA). Although it is well known that auditory fear conditioning involves synaptic potentiation in the LA, it is not clear whether the LA-BA synaptic transmission is modified upon auditory fear conditioning. Here we found that high-frequency stimulation ex vivo resulted in long-term potentiation (LTP) with a concomitant enhancement of neurotransmitter release at LA-BA synapses. Auditory fear conditioning also led to the presynaptic facilitation at LA-BA synapses. Meanwhile, AMPA/NMDA current ratio was not changed upon fear conditioning, excluding the involvement of postsynaptic mechanism. Notably, fear conditioning occluded electrically induced ex vivo LTP in the LA-BA pathway, indicating that the conditioning and electrically induced LTP share common mechanisms. Our findings suggest that the presynaptic potentiation of LA-BA synapses may be involved in fear conditioning.
外侧杏仁核（LA）是皮质和丘脑区域的主要感觉输入部位。反过来，LA 谷氨酸能锥体神经元强烈投射到基底杏仁核（BA）。虽然众所周知听觉恐惧条件反射涉及 LA 中的突触增强，但尚不清楚听觉恐惧条件反射是否会改变 LA-BA 的突触传递。在这里，我们发现离体高频刺激导致长时程增强（LTP），同时增强 LA-BA 突触处神经递质的释放。听觉恐惧条件反射也导致 LA-BA 突触的突触前易化。同时，恐惧条件反射后 AMPA/NMDA 电流比没有变化，排除了突触后机制的参与。值得注意的是，恐惧条件反射阻断了 LA-BA 通路中电诱导的离体 LTP，表明条件反射和电诱导的 LTP 具有共同的机制。我们的发现表明，LA-BA 突触的突触前增强可能参与恐惧条件反射。
