Premium
Anatomical Characterization Of Gαi 2 Expressing Hypothalamic Paraventricular Nucleus Neurons
Author(s) -
Chaudhary Parul,
Wainford Richard D.
Publication year - 2020
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.2020.34.s1.03986
Subject(s) - parvocellular cell , medicine , endocrinology , magnocellular cell , vasopressin , supraoptic nucleus , oxytocin , tyrosine hydroxylase , hypothalamus , in situ hybridization , homeostasis , biology , chemistry , dopamine , gene expression , biochemistry , gene
Background Hypertension is a global health burden, and excess dietary salt is an established cause of hypertension. The hypothalamic paraventricular nucleus (PVN) is an essential component of the neuronal network that regulates sodium homeostasis and blood pressure. Previously, we have shown PVN specific GPCR‐coupled Gαi 2 subunit proteins are essential to counter the development of salt‐sensitive hypertension by mediating the sympathoinhibitory and natriuretic responses to increased dietary sodium intake to maintain sodium homeostasis and normotension. However, the cellular localization and identity of PVN Gαi 2 expressing neurons is currently unknown. Objective To determine the anatomical characterization of Gαi 2 expressing PVN neurons. Methodology Three‐month‐old male (n=3) and female (n=3) Sprague Dawley rats were subjected to transcardial perfusion, and brains were post fixed in 4% paraformaldehyde and 30% sucrose. 20μm frozen brain slices were collected. Using in‐situ hybridization (ACD RNAscope kits) neuronal expression of Gαi 2 , vGLUT2, GAD67, corticotropin‐releasing hormone (CRH), tyrosine hydroxylase (TH), oxytocin, and arginine vasopressin (AVP) in hypothalamic PVN neurons was determined. The visualization and evaluation of co‐localization of Gαi 2 expressing PVN parvocellular neurons with vGLUT2, GAD67, CRH, TH, oxytocin and AVP was done using a Keyence Bz‐9000e microscope and Image J respectively. Results We observed no differences among male and female rats, therefore, all data is presented as n=6. Our data show that neurons containing Gαi 2 mRNA are localized in parvocellular but not magnocellular region of hypothalamic PVN. In the parvocellular region Gαi 2 mRNA co‐localized with 87.5 ± 3.0% of GABA expressing neurons and 25.1 ± 2.7 % of vGLUT2 neurons, signifying that the Gαi 2 mRNA is highly co‐localized with GABAergic neurons. Additionally, Gαi 2 co‐localized with 76.3 ± 5.2% of CRH neurons and 33.5 ± 1.8% of TH expressing parvocellular neurons. We observed no localization of Gαi 2 neurons with oxytocin or AVP expressing magnocellular neurons. Conclusion Given 1) our prior data demonstrate PVN Gαi 2 proteins play a critical role in mediating sympathoinhibition and, 2) that the GABA B receptor signals predominantly through a Gαi 2 pathway we speculate, given the high co‐localization of Gαi 2 mRNA with GABAergic neurons, that Gαi 2 proteins modulate GABAergic signaling to impact sympathetic outflow and blood pressure. Support or Funding Information T32 HL007224 to PC R01 HL139867 to RDW R01 HL141406 to RDW R56 AG057687 to RDW