In vivo measurement of enhanced agouti-related peptide release in the paraventricular nucleus of the hypothalamus through Gs activation of agouti-related peptide neurons

Zhenzhong Cui; Adam S Smith

doi:10.14440/jbm.2019.288

In vivo measurement of enhanced agouti-related peptide release in the paraventricular nucleus of the hypothalamus through G_s activation of agouti-related peptide neurons

J Biol Methods. 2019 Jul 4;6(3):e116. doi: 10.14440/jbm.2019.288. eCollection 2019.

Authors

Zhenzhong Cui^{1

2}, Adam S Smith^{3

4}

Affiliations

¹ Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
² Mouse Metabolism Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
³ Section on Neural Gene Expression, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
⁴ Department of Pharmacology & Toxicology, School of Pharmacy, University of Kansas, Lawrence, KS, USA.

Abstract

Agouti-related peptide (AgRP) neurons of the hypothalamus play a role in hunger-triggered food intake, stability of body weight, and long-term energy balance. A recent study showed that activation of the G_s-linked G protein-coupled receptors (GCPR) expressed by hypothalamic AgRP neurons promotes a sustained increase in food intake. Enhanced AgRP release has been the postulated underlying mechanism. Here, we confirmed that activation of G_s-coupled receptors expressed by AgRP neurons in the arcuate nucleus (ARC) of the hypothalamus, which is the primary brain region for the synthesis and release of AgRP, leads to increased release of AgRP in the paraventricular nucleus of the hypothalamus (PVN). We were unable to confirm changes in AgRP expression or intracellular content using traditional histological techniques. Thus, we developed an assay to measure AgRP in the extracellular fluid in the brain using large molecular weight cut-off microdialysis probes. Our technique enables assessment of brain AgRP pharmacokinetics under physiological conditions and in response to specific pharmacological interventions designed to modulate AgRP signaling.

Keywords: AgRP; DREADD; arcuate nucleus of the hypothalamus; in vivo microdialysis.

Abstract

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