Testing the functional role of putative synaptic contacts of core pacemaker neurons

BERNABEI CORNEJO, S.G.; PÍREZ, N.; CERIANI, M.F.

Mar del Plata

Conferencia; Reunión Anual de la Sociedad Argentina de Neurociencias; 2015

SAN

Our laboratory is interested in characterizing the neuronal circuitry involved in rhythmic behavior of Drosophila melanogaster. We have previously shown that the sLNvs, a key group of circadian neurons commanding locomotor activity behavior, undergo structural remodeling of their axonal terminals in a circadian fashion. By means of a GRASP screen we have identified several neuronal clusters contacting the sLNvs across the day. Currently, we are testing the functional role of these neuronal clusters on the control of locomotor activity, by means of overexpressing different ion channels that will either hyperpolarize or depolarize their cell membrane. In some of the neuronal clusters, constitutive overexpression of the KIR2.1 channel was lethal. In other cases, it reduced behavioral rhythmicity. To eliminate the possibility that constitutive overexpression yielded developmental defects we induced for a short time the activation of TRPA1, a depolarizing, temperature-activated ion channel, in an adult-specific manner. Interestingly, activation of a subset of the putative synaptic partners triggered behavioral defects suggesting that they are part of the circuit controlling locomotor activity. Additionally, we performed whole-brain immunohistochemistry in order to begin to characterize these novel circadian-relevant clusters. These results suggest that additional clusters (beyond the well-characterized clock neurons) are part of the Drosophila circadian network.