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Expression of functional Angiotensin II (Ang II) receptors types, AT 1 R and AT 2 R, in RVLM neuronal cultures from adult rat brain
Author(s) -
Cuadra Adolfo Ernesto,
Gillies Robert,
Sumners Colin,
Raizada Mohan K.
Publication year - 2008
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.22.1_supplement.1210.12
Subject(s) - rostral ventrolateral medulla , medicine , endocrinology , neuron , losartan , stimulation , angiotensin ii , hypothalamus , receptor , biology , chemistry , microbiology and biotechnology , neuroscience , central nervous system , medulla oblongata
Our previous studies have demonstrated that AT 1 R signaling pathway regulates RVLM neuronal activity. Their increased expression and coupling to PI3K has been linked to increased Ang II‐mediated neuronal activity in the SHR‐RVLM. These findings, obtained from mixed cultures of neonatal rat hypothalamus, may not reflect those of the RVLM in adults. Thus, our objectives in this study were to establish neuronal cultures from the RVLM of adult rats, and use them to study the effects of Ang II. GFP‐AAV viral vector was injected into the RVLM of SD rats two weeks prior to isolation of neurons for anatomical confirmation. Cells were dissociated, plated onto culture dishes and allowed to establish for 7–14 days. Presence of neuron specific markers, neuN and synaptophysin in GFP expressing cells confirmed the presence of RVLM neurons. Certain fluorescent neurons expressed AT 1 R. Ang II effect was tested on Ca 2+ currents (I Ba ) recorded from GFP expressing neurons. Ang II caused a 30% increase in I Ba that was attenuated by 2 μM losartan. However, pretreatment with AT 2 R antagonist, PD123319, resulted in 2.5 fold augmentation of Ang II‐mediated increase in I Ba . Together, these observations demonstrate that both AT 1 R and AT 2 R are present on the same neuron and that inhibition of the AT 2 R accentuates the AT 1 R‐mediated stimulation of I Ba . They suggest a functional coupling of AT 1 R and AT 2 R in the RVLM. (Supported by NIH HL 33610 and HLT6312)