Cholinergic left-right asymmetry in the habenulo-interpeduncular pathway

Elim Hong, Kirankumar Santhakumar, Courtney A. Akitake, Sang Jung Ahn, Christine Thisse, Bernard Thisse, Claire Wyart, Jean Marie Mangin, Marnie E. Halpern

Research output: Contribution to journalArticlepeer-review

Abstract

The habenulo-interpeduncular pathway, a highly conserved cholinergic system, has emerged as a valuable model to study leftright asymmetry in the brain. In larval zebrafish, the bilaterally paired dorsal habenular nuclei (dHb) exhibit prominent left-right differences in their organization, gene expression, and connectivity, but their cholinergic nature was unclear. Through the discovery of a duplicated cholinergic gene locus, we now show that choline acetyltransferase and vesicular acetylcholine transporter homologs are preferentially expressed in the right dHb of larval zebrafish. Genes encoding the nicotinic acetylcholine receptor subunits α2 and β4 are transcribed in the target interpeduncular nucleus (IPN), suggesting that the asymmetrical cholinergic pathway is functional. To confirm this, we activated channelrhodopsin-2 specifically in the larval dHb and performed whole-cell patchclamp recording of IPN neurons. The response to optogenetic or electrical stimulation of the right dHb consisted of an initial fast glutamatergic excitatory postsynaptic current followed by a slowrising cholinergic current. In adult zebrafish, the dHb are divided into discrete cholinergic and peptidergic subnuclei that differ in size between the left and right sides of the brain. After exposing adults to nicotine, fos expression was activated in subregions of the IPN enriched for specific nicotinic acetylcholine receptor subunits. Our studies of the newly identified cholinergic gene locus resolve the neurotransmitter identity of the zebrafish habenular nuclei and reveal functional asymmetry in a major cholinergic neuromodulatory pathway of the vertebrate brain.

Original languageEnglish (US)
Pages (from-to)21171-21176
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume110
Issue number52
DOIs
StatePublished - Dec 24 2013
Externally publishedYes

Keywords

  • Addiction
  • Electrophysiology
  • Optogeneticis
  • Tachykinin 1

ASJC Scopus subject areas

  • General

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