TMEM16A expression in cholinergic neurons of medial habenula mediates anxiety-related behaviors

TMEM16A, a Ca2+-activated Cl- channel, has been known to modulate the excitability of various types of cells; however, its function in central neurons has been largely unknown. In this study, we identified the specific expression of TMEM16A in the medial habenula (mHb) via RNAscope in situ hybridization, immunohistochemistry, and electrophysiology. Additionally, we found that when TMEM16A was ablated in the mHb cholinergic neurons (TMEM16A cKO mice), the slope of after-hyperpolarization of spontaneous action potentials was decreased; thus, the firing frequency was reduced. The reduced mHb activity resulted in decreasing the activity of the interpeduncular nucleus (IPN). Moreover, we found that TMEM16A cKO mice displayed anxiogenic behaviors and deficits in social interaction without despair-like phenotypes nor cognitive dysfunctions. Finally, we performed chemogenetic inhibition of mHb cholinergic neurons using the DREADD (Designer Receptors Exclusively Activated by Designer Drugs) approach, which revealed similar behavioral phenotypes to those of TMEM16A cKO mice. We conclude that TMEM16A plays a key role in anxiety-related behaviors regulated by mHb cholinergic neurons and could be a potential therapeutic target against anxiety-related disorders.