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Cell‐selective Expression of Angiotensin Type 1A Receptors In The Rostral Ventrolateral Medulla Of The Mouse
Author(s) -
Chen Daian,
Bassi Jaspreet K,
Walther Thomas,
Thomas Walter,
Allen Andrew M
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.808.11
Subject(s) - rostral ventrolateral medulla , catecholaminergic cell groups , medicine , medulla oblongata , endocrinology , angiotensin ii , catecholaminergic , microinjection , catecholamine , chemistry , renin–angiotensin system , homeostasis , receptor , biology , central nervous system , blood pressure
Brain angiotensin (AngII) regulates cardiovascular function and fluid and salt homeostasis. One brain site where AngII acts to regulate blood pressure (BP) and sympathetic nerve activity (SNA) is the rostral ventrolateral medulla (RVLM). This brain nucleus contains a population of catecholaminergic (C1) neurons that are critical for regulation of BP. We showed previously that AngII‐mediated excitation of RVLM neurons in adult mice is dependent upon the angiotensin type 1A receptor (AT 1A R). In this study, we examine the effects of inducing AT 1A R expression specifically in C1 neurons of the RVLM in AT 1A −/− mice via viral delivery. In anesthetised AT 1A −/− mice (75 μg/g ketamine, 10 μg/g xylazine IP) replication‐deficient lentiviruses, expressing AT 1A R or GFP under the control of a catecholamine‐selective promoter were microinjected into the RVLM bilaterally. We show that in RVLM, viral transgene expression only occurred in the catecholaminergic neurons and produced stable expression of AT 1 R detected by quantitative autoradiography. In further experiments following viral injections, mice were tracheotomised, and BP and SNA recorded. Microinjection of AngII (1 mM, 50 nl) into RVLM of lentiviral AT 1A expressing mice increased BP (21±4 mmHg) and SNA. These results establish that activation of the C1 catecholamine neurons of the RVLM causes a sympathetically mediated pressor response.