SIFamide Translates Hunger Signals into Appetitive and Feeding Behavior in Drosophila

Abstract

Animal behavior is, on the one hand, controlled by neuronal circuits that integrate external sensory stimuli and induce appropriate motor responses. On the other hand, stimulus-evoked or internally generated behavior can be influenced by motivational conditions, e.g., the metabolic state. Motivational states are determined by physiological parameters whose homeostatic imbalances are signaled to and processed within the brain, often mediated by modulatory peptides. Here, we investigate the regulation of appetitive and feeding behavior in the fruit fly, Drosophila melanogaster. We report that four neurons in the fly brain that release SIFamide are integral elements of a complex neuropeptide network that regulates feeding. We show that SIFamidergic cells integrate feeding stimulating (orexigenic) and feeding suppressant (anorexigenic) signals to appropriately sensitize sensory circuits, promote appetitive behavior, and enhance food intake. Our study advances the cellular dissection of evolutionarily conserved signaling pathways that convert peripheral metabolic signals into feeding-related behavior.

Neuropeptide relay between SIFa signaling controls the experience-dependent mating duration of male Drosophila

“…By acute activation in SIFa neurons, non-starved flies act starve-like and enhance their food intake. Interestingly, SIFa integrates orexigenic signals from myoinhibitory peptide neurons and anorexigenic signals from Hugin-pyrokinin neurons to mediate satiety and hunger [12]. This report suggests that SIFa neurons are important to recruiting compensatory pathways via other neuropeptides to facilitate hunger-driven behaviour.…”

“…Previous studies have reported a link between SIFa and interval timing behaviours [12,28], but no prior studies have identified a direct connection to mating duration. Our study showed that depolarizing SIFa neurons initiates LMD while hyperpolarizing displays SMD.…”

“…SIFa was first identified in grey fleshfly Neobellieria bullata [16][17][18] and is expressed by four neurons located in the pars intercerebralis which is well distributed throughout the brain and VNC by its morphology [19]. This neuropeptide has significant impact on various behaviours including appetite [12], courtship [17], and sleep [20]. However, the mechanism of SIFa signaling controlling various behaviours is not well understood.…”

A neuroendocrine pathway modulating osmotic stress inDrosophila

“…In addition, Crz neurons appear to innervate the antennal lobe (AL) ( Figure S2D), which show high expression of CrzR (Figure S2A-C). Perhaps, Crz modulates odor sensitivity in hungry flies similar to sNPF, tachykinin and SIFamide in order to increase food search [60][61][62]. The AKH receptor is expressed in sweet-sensing gustatory receptor (Gr5a) neurons [63].…”

Satiation State-dependent Dopaminergic Control of Food Seeking in Drosophila

“…The PAM neurons are also heterogeneous, sending pro-jections that tile to well-defined regions of the mushroom body and to regions of the protocerebrum. Specific subsets of PAM neurons that are included in the 0273-Gal4 pattern have been implicated in various forms of appetitive learning and memory, however their inactivation did not impact food seeking in food deprived flies (not shown) 15,17,[37][38][39] . This suggests that there may be further segregation of PAM dopamine neuron function, possibly according to innate and learned appetitive responses.…”