title: Reporter mouse strain provides a novel look at angiotensin type-2 receptor distribution in the central nervous system.
abstract: Angiotensin-II acts at its type-1 receptor (AT1R) in the brain to regulate body fluid homeostasis, sympathetic outflow and blood pressure. However, the role of the angiotensin type-2 receptor (AT2R) in the neural control of these processes has received far less attention, largely because of limited ability to effectively localize these receptors at a cellular level in the brain. The present studies combine the use of a bacterial artificial chromosome transgenic AT2R-enhanced green fluorescent protein (eGFP) reporter mouse with recent advances in in situ hybridization (ISH) to circumvent this obstacle. Dual immunohistochemistry (IHC)/ISH studies conducted in AT2R-eGFP reporter mice found that eGFP and AT2R mRNA were highly co-localized within the brain. Qualitative analysis of eGFP immunoreactivity in the brain then revealed localization to neurons within nuclei that regulate blood pressure, metabolism, and fluid balance (e.g., NTS and median preoptic nucleus [MnPO]), as well as limbic and cortical areas known to impact stress responding and mood. Subsequently, dual IHC/ISH studies uncovered the phenotype of specific populations of AT2R-eGFP cells. For example, within the NTS, AT2R-eGFP neurons primarily express glutamic acid decarboxylase-1 (80.3 ± 2.8 %), while a smaller subset express vesicular glutamate transporter-2 (18.2 ± 2.9 %) or AT1R (8.7 ± 1.0 %). No co-localization was observed with tyrosine hydroxylase in the NTS. Although AT2R-eGFP neurons were not observed within the paraventricular nucleus (PVN) of the hypothalamus, eGFP immunoreactivity is localized to efferents terminating in the PVN and within GABAergic neurons surrounding this nucleus. These studies demonstrate that central AT2R are positioned to regulate blood pressure, metabolism, and stress responses.
authors.affiliation: Department of Physiology and Functional Genomics, College of Medicine, McKnight Brain Institute, University of Florida, 100 S. Newell Drive (Bldg. 59, RM L4-162), Gainesville, FL, 32611, USA. adekloet@ufl.edu.
authors.forename: Annette D
authors.initials: AD
authors.lastname: de Kloet
authors.affiliation: Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, 32611, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Physiology and Functional Genomics, College of Medicine, McKnight Brain Institute, University of Florida, 100 S. Newell Drive (Bldg. 59, RM L4-162), Gainesville, FL, 32611, USA.
authors.forename: Jacob A
authors.initials: JA
authors.lastname: Ludin
authors.affiliation: Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, 32611, USA.
authors.forename: Justin A
authors.initials: JA
authors.lastname: Smith
authors.affiliation: Department of Physiology and Functional Genomics, College of Medicine, McKnight Brain Institute, University of Florida, 100 S. Newell Drive (Bldg. 59, RM L4-162), Gainesville, FL, 32611, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Pioquinto
authors.affiliation: Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, 32611, USA.
authors.forename: Helmut
authors.initials: H
authors.lastname: Hiller
authors.affiliation: Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense C, Denmark.
authors.forename: U Muscha
authors.initials: UM
authors.lastname: Steckelings
authors.affiliation: Department of Physiology and Functional Genomics, College of Medicine, McKnight Brain Institute, University of Florida, 100 S. Newell Drive (Bldg. 59, RM L4-162), Gainesville, FL, 32611, USA.
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Scheuer
authors.affiliation: Department of Physiology and Functional Genomics, College of Medicine, McKnight Brain Institute, University of Florida, 100 S. Newell Drive (Bldg. 59, RM L4-162), Gainesville, FL, 32611, USA.
authors.forename: Colin
authors.initials: C
authors.lastname: Sumners
authors.affiliation: Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, 32611, USA.
authors.forename: Eric G
authors.initials: EG
authors.lastname: Krause
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D002490:Central Nervous System / Q000378:metabolism*; D059330:GABAergic Neurons / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D023421:Models, Animal; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D011301:Preoptic Area / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D044139:Receptor, Angiotensin, Type 2 / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D050599:Vesicular Glutamate Transport Protein 2 / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D044139:Receptor, Angiotensin, Type 2; D050599:Vesicular Glutamate Transport Protein 2; D014446:Tyrosine 3-Monooxygenase
keywords: AT2; Blood pressure; Brain; Hypertension; Renin