Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
Nat Neurosci. 2011 Feb;14(2):190-9. doi: 10.1038/nn.2716. Epub 2010 Dec 26.
Adrenergic signaling has important roles in synaptic plasticity and metaplasticity. However, the underlying mechanisms of these functions remain poorly understood. We investigated the role of octopamine, the invertebrate counterpart of adrenaline and noradrenaline, in synaptic and behavioral plasticity in Drosophila. We found that an increase in locomotor speed induced by food deprivation was accompanied by an activity- and octopamine-dependent extension of octopaminergic arbors and that the formation and maintenance of these arbors required electrical activity. Growth of octopaminergic arbors was controlled by a cAMP- and CREB-dependent positive-feedback mechanism that required Octβ2R octopamine autoreceptors. Notably, this autoregulation was necessary for the locomotor response. In addition, octopamine neurons regulated the expansion of excitatory glutamatergic neuromuscular arbors through Octβ2Rs on glutamatergic motor neurons. Our results provide a mechanism for global regulation of excitatory synapses, presumably to maintain synaptic and behavioral plasticity in a dynamic range.
肾上腺素能信号在突触可塑性和超可塑性中具有重要作用。然而，这些功能的潜在机制仍知之甚少。我们研究了章鱼胺（肾上腺素和去甲肾上腺素的无脊椎动物对应物）在果蝇突触和行为可塑性中的作用。我们发现，食物剥夺引起的运动速度增加伴随着章鱼胺能树突的活性和章鱼胺依赖性延伸，而这些树突的形成和维持需要电活性。章鱼胺能树突的生长受 cAMP 和 CREB 依赖性正反馈机制的控制，该机制需要 Octβ2R 章鱼胺自受体。值得注意的是，这种自身调节对于运动反应是必需的。此外，章鱼胺神经元通过谷氨酸能运动神经元上的 Octβ2R 调节兴奋性谷氨酸能肌神经末梢的扩展。我们的结果提供了一种兴奋性突触的全局调节机制，可能是为了在动态范围内维持突触和行为可塑性。
