GSBS Student Publications

Autoregulatory and paracrine control of synaptic and behavioral plasticity by octopaminergic signaling

Alex C. Koon, University of Massachusetts Medical School
James A. Ashley, University of Massachusetts Medical School
Romina Barria, University of Massachusetts Medical School
Shamik DasGupta, University of Massachusetts Medical School
Ruth Brain, University of Massachusetts Medical School
Scott Waddell, University of Massachusetts Medical School
Mark J. Alkema, University of Massachusetts Medical School
Vivian Budnik, University of Massachusetts Medical School

Document Type Article

Abstract

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 Octbeta2R octopamine autoreceptors. Notably, this autoregulation was necessary for the locomotor response. In addition, octopamine neurons regulated the expansion of excitatory glutamatergic neuromuscular arbors through Octbeta2Rs 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.