VGAT and VGLUT2 expression in MCH and orexin neurons in double transgenic reporter mice

• Published in: IBRO reports 2018-06, Vol.4, p.44-49
• Main Authors: Blanco-Centurion, Carlos, Bendell, Emmaline, Zou, Bingyu, Sun, Ying, Shiromani, Priyattam J., Liu, Meng
• Format: Article
• Language: English
• Subjects: Arousal; GABA; Glutamate; Sleep
• ISSN: 2451-8301; 2451-8301
• DOI: 10.1016/j.ibror.2018.05.001

•MCH neurons contain neither VGAT nor VGLUT2.•Majority of orexin neurons contain VGLUT2.•MCH neurons do not contain orexin. The neuropeptides orexin and melanin-concentrating hormone (MCH), as well as the neurotransmitters GABA (γ-Aminobutyric acid) and glutamate are chief modulators of the sleep-wake states in the posterior hypothalamus. To investigate co-expression of vesicular GABA transporter (VGAT, a marker of GABA neurons) and the vesicular glutamate transporter-2 (VGLUT2, a marker of glutamate neurons) in orexin and MCH neurons, we generated two transgenic mouse lines. One line selectively expressed the reporter gene EYFP in VGAT+ neurons, whereas the other line expressed reporter gene tdTomato in VGLUT2+ neurons. Co-localization between these genetic reporters and orexin or MCH immunofluorescent tags was determined using 3D computer reconstructions of Z stacks that were acquired using a multiphoton laser confocal microscope. Our results demonstrated that MCH neurons expressed neither VGAT nor VGLUT2, suggesting MCH neurons are a separate cluster of cells from VGAT+ GABAergic neurons and VGLUT2+ glutamatergic neurons. Moreover, most orexin neurons expressed VGLUT2, indicating these neurons are glutamatergic. Our data suggested that in the posterior hypothalamus there are four major distinct groups of neurons: VGAT+, orexin+/VGLUT2+, orexin-/VGLUT2+, and MCH neurons. This study facilitated our understanding of the role of these neurotransmitters and neuropeptides in relation to sleep/wake regulation.