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Expression of angiotensin type 1A receptors in C1 neurons of the rostral ventrolateral medulla is required for the pressor response to angiotensin II
Author(s) -
Allen Andrew Mark,
Jancovski Nikola,
Choong Yan-Ting,
Carter David A,
Gurley Susan B,
Chen Daian,
Bassi Jaspreet Kaur
Publication year - 2012
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.26.1_supplement.1091.7
Subject(s) - rostral ventrolateral medulla , medicine , endocrinology , angiotensin ii , medulla oblongata , chemistry , renin–angiotensin system , paraformaldehyde , glutamate receptor , receptor , biology , blood pressure , central nervous system , organic chemistry
Angiotensin II (AngII) acts via its type 1A receptor (AT 1A R) in the rostral ventrolateral medulla (RVLM) to modulate blood pressure. Whilst AngII is known to excite RVLM C1 neurons, it is not known whether this is sufficient for the pressor response in vivo . Using an AT 1A R promoter GFP mouse we examined expression within RVLM. Mice (n=3) were anesthetized and perfused with 4% paraformaldehyde for immunohistochemical detection of GFP and tyrosine hydroxylase (TH). To determine whether AT 1A Rs in C1 neurons are necessary for the pressor response to AngII in RVLM, lentivirus expressing either Cre‐recombinase (Cre)(n=6) or GFP (n=6) controlled by a phox2 promoter was injected into the RVLM, in adult transgenic mice with a conditional AT 1A R allele (AT 1A R fl/fl ). Four weeks after viral injection, blood pressure was recorded in anesthetized mice. Ang II (50 nL of 1 mM) and glutamate (10 nL of 10 mM) were injected into the RVLM. Immunohistochemistry revealed that the majority of C1 neurons expressed the AT 1A R. A small number of AT 1A R‐expressing non‐ C1 neurons were observed. Cre expression in the RVLM of AT 1A R fl/fl mice did not affect the response to glutamate but attenuated the response to AngII (Cre: 3±(SD)3.4 mmHg; GFP: 17±(SD)5.2 mmHg P<0.001). Expression of the AT 1A R occurs endogenously in C1 neurons and is essential for the pressor response to AngII in the RVLM. Supported by the NHMRC (Australia).