Open AccessOptogenetic activation of septal GABAergic afferents entrains neuronal firing in the medial habenula
Author(s) -
Kyuhyun Choi,
Young In Lee,
Chang-Woo Lee,
Seong-Kwan Hong,
Soonje Lee,
Seok-Jίn Kang,
Ki Soon Shin
Publication year - 2016
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep34800
Subject(s) - gabaa receptor , gabab receptor , neuroscience , inhibitory postsynaptic potential , excitatory postsynaptic potential , gabaergic , optogenetics , biology , bicuculline , chemistry , receptor , biochemistry
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 GABA A receptors and GABA B receptors. Depending on intracellular chloride concentration, however, GABA A receptors 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 GABA A receptor-mediated synaptic currents, which produced stimulus-locked neuronal firing. Subsequent delayed yet lasting activation of GABA B receptors attenuated the intrinsic tonic firing. Consequently, septal GABAergic input alone orchestrates both excitatory GABA A and inhibitory GABA B receptors, thereby entraining the firing of MHb neurons.