Serotonin acts through multiple cellular targets during an olfactory critical period

Ahana Mallick; Hua Leonhard Tan; Jacob Michael Epstein; Clarissa Mei Jing Ng; Oliver Mason Cook; Quentin Gaudry; Andrew M Dacks

doi:10.1016/j.isci.2024.111083

Serotonin acts through multiple cellular targets during an olfactory critical period

iScience. 2024 Oct 9;27(11):111083. doi: 10.1016/j.isci.2024.111083. eCollection 2024 Nov 15.

Authors

Ahana Mallick¹, Hua Leonhard Tan¹, Jacob Michael Epstein¹, Clarissa Mei Jing Ng¹, Oliver Mason Cook², Quentin Gaudry¹, Andrew M Dacks^{2

3}

Affiliations

¹ Department of Biology, University of Maryland, College Park, MD 20742, USA.
² Departments of Biology and Neuroscience, West Virginia University, Morgantown, WV 26505, USA.
³ Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA.

Abstract

Serotonin (5-HT) modulates early development during critical periods when experience drives heightened levels of plasticity in neurons. Here, we investigate the cellular mechanisms by which 5-HT modulates critical period plasticity (CPP) in the olfactory system of Drosophila. We first demonstrate that 5-HT is necessary for experience-dependent structural plasticity in response to chronic CO₂ exposure and can re-open the critical period long after it normally closes. Knocking down 5-HT7 receptors in a subset of GABAergic local interneurons was sufficient to block CPP, as was knocking down GABA receptors expressed by CO₂-sensing olfactory sensory neurons (OSNs). Furthermore, direct modulation of OSNs via 5-HT2B receptors in CO₂-sensing OSNs and autoreceptor expression by serotonergic neurons was also required for CPP. Thus, 5-HT targets individual neuron types in the olfactory system via distinct receptors to enable sensory driven plasticity.

Keywords: Molecular neuroscience; Sensory neuroscience.