Circuitry and neurochemical signature of projections between the lateral habenula, the rostromedial tegmental nucleus and the dorsal raphe nucleus.

Author(s)

Chemutai Sego

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2013-06-27

Examining board members

Jackson Cioni Bittencourt; Luciano Freitas Felicio; Martin Andreas Metzger

• Advisor: Jackson Cioni Bittencourt

Abstract

The lateral habenula (LHb) inhibits mesencephalic dopamine neurons through a mesopontine GABAergic node, the rostromedial tegmental nucleus (RMTg). Both LHb and RMTg also project to the dorsal raphe nucleus (DR). The organization of LHb and RMTg projections to the DR was investigated using anterograde tracer injections into the LHb or RMTg and confirmed with retrograde tracer injections. To identify the neurochemical phenotype of RMTg-DR projections, we associated in situ hybridization for GAD67 mRNA with immunohistochemical detection of retrograde tracers deposited in the DR. DR target regions of RMTg projections were characterized using double-imunofluorescence techniques for the anterograde tracer deposited into the RMTg and either serotonin or the type 3 vesicular glutamate transporter. We detected a focal direct projection from the medial LHb division to the caudal DR. In contrast the RMTg emits robust GABAergic projections to a central DR subdivision rich in presumptive glutamatergic neurons. (AU)

• FAPESP's process: 11/03292-7 - Circuitry and neurochemical signature of the projections among the lateral habenula, the rostromedial tegmental nucleus and the dorsal raphe nucleus
• Grantee: Chemutai Sego
• Support Opportunities: Scholarships in Brazil - Master