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G?i2-protein-mediated signal transduction: central nervous system molecular mechanism countering the development of sodium-dependent hypertension.

ABSTRACT: Excess dietary salt intake is an established cause of hypertension. At present, our understanding of the neuropathophysiology of salt-sensitive hypertension is limited by a lack of identification of the central nervous system mechanisms that modulate sympathetic outflow and blood pressure in response to dietary salt intake. We hypothesized that impairment of brain G?i2-protein-gated signal transduction pathways would result in increased sympathetically mediated renal sodium retention, thus promoting the development of salt-sensitive hypertension. To test this hypothesis, naive or renal denervated Dahl salt-resistant and Dahl salt-sensitive (DSS) rats were assigned to receive a continuous intracerebroventricular control scrambled or a targeted G?i2-oligodeoxynucleotide infusion, and naive Brown Norway and 8-congenic DSS rats were fed a 21-day normal or high-salt diet. High salt intake did not alter blood pressure, suppressed plasma norepinephrine, and evoked a site-specific increase in hypothalamic paraventricular nucleus G?i2-protein levels in naive Brown Norway, Dahl salt-resistant, and scrambled oligodeoxynucleotide-infused Dahl salt-resistant but not DSS rats. In Dahl salt-resistant rats, G?i2 downregulation evoked rapid renal nerve-dependent hypertension, sodium retention, and sympathoexcitation. In DSS rats, G?i2 downregulation exacerbated salt-sensitive hypertension via a renal nerve-dependent mechanism. Congenic-8 DSS rats exhibited sodium-evoked paraventricular nucleus-specific G?i2-protein upregulation and attenuated hypertension, sodium retention, and global sympathoexcitation compared with DSS rats. These data demonstrate that paraventricular nucleus G?i2-protein-gated pathways represent a conserved central molecular pathway mediating sympathoinhibitory renal nerve-dependent responses evoked to maintain sodium homeostasis and a salt-resistant phenotype. Impairment of this mechanism contributes to the development of salt-sensitive hypertension.

SUBMITTER: Wainford RD

PROVIDER: S-EPMC4268057 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature

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Gαi2-protein-mediated signal transduction: central nervous system molecular mechanism countering the development of sodium-dependent hypertension.

Wainford Richard D RD Carmichael Casey Y CY Pascale Crissey L CL Kuwabara Jill T JT

Hypertension (Dallas, Tex. : 1979) 20141013 1

Excess dietary salt intake is an established cause of hypertension. At present, our understanding of the neuropathophysiology of salt-sensitive hypertension is limited by a lack of identification of the central nervous system mechanisms that modulate sympathetic outflow and blood pressure in response to dietary salt intake. We hypothesized that impairment of brain Gαi2-protein-gated signal transduction pathways would result in increased sympathetically mediated renal sodium retention, thus promo ...[more]

PMID: 25312437

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G?i2-protein-mediated signal transduction: central nervous system molecular mechanism countering the development of sodium-dependent hypertension.

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Gαi2-protein-mediated signal transduction: central nervous system molecular mechanism countering the development of sodium-dependent hypertension.

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