A NEW HAND IN THE CLOCK: INHIBITORY TRANSMISSION IN CIRCADIAN PACEMAKERS OF DROSOPHILA

LIA FRENKEL; GUILLERMO BERNABÓ; NARA I MURARO ; M. FERNANDA CERIANI

Tunuyán- Mendoza

Congreso; XII Latin American Symposium on Chronobiology; 2013

Latin American Symposium on Chronobiology

The small ventral lateral neurons (sLNvs) constitute the major pacemaker in Drosophila´s brain. Under constant conditions they guide the temporal organization of daily locomotor activity. Besides PDF-(pigment dispersing factor)-filled vesicles, they also contain small clear vesicles putatively packed with a fast neurotransmitter potentially involved in synchronizing the circadian network. Here we show the results of a screen aimed at identifying this neurotransmitter by evaluating flies? locomotor activity pattern after disrupting either membrane or vesicular neurotransmitter transporters (NTT) function, specifically within PDF neurons. We found that interfering glycine transporter expression increases period length in almost an hour without affecting rhythmicity. A decrease in intracellular glycine availability seems to underlie period lengthening as disrupting glycine synthesis has a similar effect. Daily oscillations in PDF levels at the sLNvs axonal termini are decreased under such conditions. The pursuit of glycinergic targets by immunohistochemistry revealed that PDF neurons express glycine receptors. Behaviorally, interfering glycine receptor in PDF neuron, decreases rhythmicity. Whether sLNvs glycinergic transmission entails cluster synchronization is still unknown. Current experiments will shed light on this issue.