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Modulation of p66Shc impairs cerebrovascular myogenic tone in low renin but not low nitric oxide models of systemic hypertension
- Source :
- Am J Physiol Heart Circ Physiol
- Publication Year :
- 2021
-
Abstract
- Cerebral blood flow and perfusion are tightly maintained through autoregulation despite changes in transmural pressure. Oxidative stress impairs cerebral blood flow, precipitating cerebrovascular events. Phosphorylation of the adaptor protein p66Shc increases mitochondrial-derived oxidative stress. The effect of p66Shc gain or loss of function in nonhypertensive rats is unclear. We hypothesized that p66Shc gain of function would impair autoregulation of cerebral microcirculation under physiological and pathological conditions. Three previously established transgenic [salt-sensitive (SS) background] p66Shc rats were used, p66-Del/SS (express p66Shc with a nine-amino acid deletion), p66Shc-knockout (KO)/SS (frameshift premature termination codon), and p66Shc signaling and knock-in substitution of Ser36Ala (p66Shc-S36A)/SS (substitution of Ser36Ala). The p66Shc-Del were also bred on Sprague-Dawley (SD) backgrounds (p66-Del/SD), and a subset was exposed to a hypertensive stimulus [N(G)-nitro-l-arginine methyl ester (l-NAME)] for 4 wk. Active and passive diameters to increasing transmural pressure were measured and myogenic tone was calculated in all groups (SS and SD). Myogenic responses to increasing pressure were impaired in p66Shc-Del/SS rats relative to wild-type (WT)/SS and knock-in substitution of Ser36Ala (S36A; P < 0.05). p66-Del/SD rats did not demonstrate changes in active/passive diameters or myogenic tone relative to WT/SD but did demonstrate attenuated passive diameter responses to higher transmural pressure relative to p66-Del/SS. Four weeks of a hypertensive stimulus (l-NAME) did not alter active or passive diameter responses to increasing transmural pressure (P = 0.86–0.99), but increased myogenic responses relative to p66-Del/SD (P < 0.05). Collectively, we demonstrate the functional impact of p66Shc within the cerebral circulation and demonstrate that the genetic background of p66Shc rats largely drives changes in cerebrovascular function. NEW & NOTEWORTHY We demonstrate that the modulation of p66Shc signaling impairs cerebral artery myogenic tone in a low renin model of hypertension. This impairment is dependent upon the genetic background, as modulated p66Shc signaling in Sprague-Dawley rats does not impair cerebral artery myogenic tone.
- Subjects :
- Male
medicine.medical_specialty
Middle Cerebral Artery
Src Homology 2 Domain-Containing, Transforming Protein 1
Physiology
Cerebral arteries
Blood Pressure
medicine.disease_cause
Nitric Oxide
Nitric oxide
Rats, Sprague-Dawley
chemistry.chemical_compound
Physiology (medical)
Internal medicine
Renin–angiotensin system
Renin
medicine
Animals
Homeostasis
Sodium Chloride, Dietary
Rats, Inbred Dahl
Rapid Report
business.industry
Disease Models, Animal
Endocrinology
NG-Nitroarginine Methyl Ester
chemistry
Cerebrovascular Circulation
Hypertension
Female
Rats, Transgenic
Cardiology and Cardiovascular Medicine
business
Oxidative stress
Myogenic tone
Subjects
Details
- ISSN :
- 15221539
- Volume :
- 321
- Issue :
- 6
- Database :
- OpenAIRE
- Journal :
- American journal of physiology. Heart and circulatory physiology
- Accession number :
- edsair.doi.dedup.....449c757c71a9f53b3a8e8b3029712ecd