Long-term enhancement of synaptic transmission between antennal lobe and mushroom body in cultured Drosophila brain
Long-term enhancement of synaptic transmission between antennal lobe and mushroom body in cultured Drosophila brain
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DOI：
10.1113/jphysiol.2012.242909
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发表时间：
2013-01-01
影响因子：
5.5
通讯作者：
Saitoe, Minoru
中科院分区：
文献类型：
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作者：
Ueno, Kohei;Naganos, Shintaro;Saitoe, Minoru
在果蝇中，蘑菇体(MB)是嗅觉联想学习的关键大脑结构。在厌恶条件反射中，MBS被认为是将由触角叶(AL)的投射神经元(PN)传递的气味信号与通过腹神经索(AFV)的上行纤维传递的电击信号联系在一起。虽然AL和MB之间的突触传递可能在嗅觉联想学习中起着至关重要的作用，但其生理特性尚未被直接检测。利用培养的果蝇脑，在大脑微核表达一种钙指示剂，我们研究了ALMB突触的突触传递和可塑性。在玻璃微电极刺激下，AL诱导的MBS内钙离子反应是通过果蝇烟碱型乙酰胆碱受体(DnAChRs)介导的，而AFV诱导的钙反应是通过果蝇NMDA受体(DNRs)介导的。联合刺激AL和AFV后2 h以上，ALMB突触传递增强，这种长期增强作用(LTE)仅在ALMB突触上形成，而在AFVMB突触上没有。强烈刺激AL不能单独诱导ALMB LTE，重复刺激AL后LTE在60min内衰减。ALMB LTE的这些关联性、输入特异性和持久性的表型使人高度联想到嗅觉记忆。此外，与嗅觉厌恶记忆类似，ALMB LTE的形成需要在联想刺激中激活果蝇D1多巴胺受体DOPR以及dnAChR和DNR。这些生理和遗传类比表明，ALMB LTE可能是一个与嗅觉记忆相关的细胞模型。
In Drosophila, the mushroom body (MB) is a critical brain structure for olfactory associative learning. During aversive conditioning, the MBs are thought to associate odour signals, conveyed by projection neurons (PNs) from the antennal lobe (AL), with shock signals conveyed through ascending fibres of the ventral nerve cord (AFV). Although synaptic transmission between AL and MB might play a crucial role for olfactory associative learning, its physiological properties have not been examined directly. Using a cultured Drosophila brain expressing a Ca2+ indicator in the MBs, we investigated synaptic transmission and plasticity at the ALMB synapse. Following stimulation with a glass micro-electrode, AL-induced Ca2+ responses in the MBs were mediated through Drosophila nicotinic acetylcholine receptors (dnAChRs), while AFV-induced Ca2+ responses were mediated through Drosophila NMDA receptors (dNRs). ALMB synaptic transmission was enhanced more than 2 h after the simultaneous associative-stimulation of AL and AFV, and such long-term enhancement (LTE) was specifically formed at the ALMB synapses but not at the AFVMB synapses. ALMB LTE was not induced by intense stimulation of the AL alone, and the LTE decays within 60 min after subsequent repetitive AL stimulation. These phenotypes of associativity, input specificity and persistence of ALMB LTE are highly reminiscent of olfactory memory. Furthermore, similar to olfactory aversive memory, ALMB LTE formation required activation of the Drosophila D1 dopamine receptor, DopR, along with dnAChR and dNR during associative stimulations. These physiological and genetic analogies indicate that ALMB LTE might be a relevant cellular model for olfactory memory.