Unlocking the secrets of serotonin: the effects on feeding, locomotion and adiposity in Drosophila melanogaster

Abstract

Feeding is a fundamental and defining behavior of heterotrophic organisms and its regulation is important for the fitness of an animal. Serotonin, a master modulator, mediates internal states, modifies existing neural circuits, and regulates multiple behaviors including feeding across all animal species, including humans and fruit flies. However, an in-depth study on the neuromodulatory effects of serotonin on feeding and related behaviors has been held back for several technical reasons. In this work, we used optogenetics and genetic methods to study the systemic effect of serotonin related manipulations on ongoing feeding behavior. We analyze the finer details of the feeding pattern of these flies – also called the feeding microstructure – to elucidate the subtle changes in the feeding aspects controlled by serotonin. We delve into the modulation of this microstructure in different hunger states. We also study the behavior within the context of locomotion and touch upon the differences in feeding aspects in the free and restrained state. We show that serotonin affects multiple parameters in a state-dependent manner and regulates the behaviors differently under a free and restrained state of the animal. We elucidate the role of serotonin receptors in feeding and show that different receptors promote and suppress feeding. We further investigate how chronic alterations in serotonin release from central serotonergic cells may affect the insulin production from brain insulin producing cells and alter the fat storage in the abdominal fat body and visceral organs like intestines.

Date of Award	2023
Original language	American English
Awarding Institution	HBKU College of Health & Life Sciences