title: Optogenetic activation of septal GABAergic afferents entrains neuronal firing in the medial habenula.
abstract: The medial habenula (MHb) plays an important role in nicotine-related behaviors such as nicotine aversion and withdrawal. The MHb receives GABAergic input from the medial septum/diagonal band of Broca (MS/DB), yet the synaptic mechanism that regulates MHb activity is unclear. GABA (γ -aminobutyric acid) is a major inhibitory neurotransmitter activating both GABAAreceptors and GABABreceptors. Depending on intracellular chloride concentration, however, GABAAreceptors also function in an excitatory manner. In the absence of various synaptic inputs, we found that MHb neurons displayed spontaneous tonic firing at a rate of about ~4.4 Hz. Optogenetic stimulation of MS/DB inputs to the MHb evoked GABAAreceptor-mediated synaptic currents, which produced stimulus-locked neuronal firing. Subsequent delayed yet lasting activation of GABABreceptors attenuated the intrinsic tonic firing. Consequently, septal GABAergic input alone orchestrates both excitatory GABAAand inhibitory GABABreceptors, thereby entraining the firing of MHb neurons.
authors.affiliation: Department of Biology, Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, Republic of Korea.
authors.forename: Kyuhyun
authors.initials: K
authors.lastname: Choi
authors.affiliation: Department of Biology, Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, Republic of Korea.
authors.forename: Youngin
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Biology, Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, Republic of Korea.
authors.forename: Changwoo
authors.initials: C
authors.lastname: Lee
authors.affiliation: Department of Molecular Biology, Sejong University, Seoul, Republic of Korea.
authors.forename: Seokheon
authors.initials: S
authors.lastname: Hong
authors.affiliation: Department of Biology, Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, Republic of Korea.
authors.forename: Soonje
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Molecular Biology, Sejong University, Seoul, Republic of Korea.
authors.forename: Shin Jung
authors.initials: SJ
authors.lastname: Kang
authors.affiliation: Department of Biology, Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, Republic of Korea.
authors.forename: Ki Soon
authors.initials: KS
authors.lastname: Shin
mesh_terms: D000818:Animals; D019262:Habenula / Q000502:physiology*; D008297:Male; D051379:Mice; D009474:Neurons / Q000502:physiology*; D062308:Optogenetics / Q000379:methods*; D011963:Receptors, GABA-A / Q000378:metabolism*; D009435:Synaptic Transmission; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid