Cholinergic Transmission in the Circadian Pacemaker of Drosophila

FRENKEL LIA; MILDINER SEBASTIAN; CERIANI, M. FERNANDA

Congreso; Congreso de la Federación de Asociaciones Latinoamericanas y del Caribe de Neurociencias 2016; 2016

The centralcircadian oscillator of Drosophilamelanogaster is composed of about 150 neurons organized in clusters,defined by their anatomical location. Among them, the lateral ventral neurons, smalland large LNvs, are central in the temporal organization of the fly dailylocomotor activity. These neurons release a neuropeptide called PigmentDispersing Factor. While the relevance of the PDF released by the sLNvs in thesynchronization of the circadian network is well established, the role of fastneurotransmission is still under debate. We have recently established that LNvsrelease glycine. Notwithstanding, excitatory cholinergic transmission may alsobe implicated. To uncover the role of acetylcholine in the LNvs, we downregulatedthe expression of the vesicular acetylcholine transporter, the choline-AcetylCoAtransferase and a protein postulated as the high-affinity choline transporter.We found that the temporal organization of locomotor activity is altered underthese conditions. A reduction in the levels of any of the three enzymes lengthensthe activity period in free running conditions. Additionally, a loss in theconsolidation of the activity was detected. We are in the process of definingwhich group of LNvs is responsible for the behavioral phenotype and whetherreducing acetylcholine availability affects additional sLNv outputs. We proposethat LNvs make use of both fast excitatory and inhibitory signals in favor oforganizing a coherent firing pattern in the circadian circuit.