Fast communication within the network that controls the fly´s daily behaviors

LIA FRENKEL

Mendoza

Simposio; X Congreso Argentino de Entomología- Simposio de Neurobiología de Insectos; 2018

X Congreso Argentino de Entomología

The central circadian oscillator of Drosophila melanogaster is composed of about 150 neurons. Among them, the 8 small lateral ventral neurons (sLNvs) are fundamental in various aspects of temporal organization,but by far the most studied one is in the fly daily locomotor activity. sLNvs release PDF, the neuropeptide that synchronizes circadian oscillators. While the relevance of neuropeptidergic transmission is well established, uncovering the role of fast neurotransmissionis booming. After a screen aimed at unveiling sLNv neurotransmitter identity, we established that sLNvs release glycine. Glycinergic transmission inhibits sLNv post-synaptic targets. Notwithstanding, our results also suggest that sLNvs recruit excitatory cholinergictransmission for communication. Unexpectedly, acetylcholine depletion in these neurons by downregulating its synthesis, recycling or synaptic vesicle refilling, leads to a lengthening in the period of locomotor activity, as it is the case with glycinergic transmission,suggesting that period lengthening is the result of altering the hierarchical relationship among clusters The ?one neuron, one neurotransmitter? dogma has repeatedly been questioned by findings within the mammalian brain, where co-transmission seems to be therule. In addition, it has been proposed that co-transmission would play a role in plasticity. Since reorganization of synaptic circuits by neurotransmitter switching can occur in response to changes in the environment or nutritional state, we propose that temporalsegregating the synaptic vesicular content contributes to the functional rewiring of the circadian network in Drosophila.