Dataset Information

Aging-related alterations in eNOS and nNOS responsiveness and smooth muscle reactivity of murine basilar arteries are modulated by apocynin and phosphorylation of myosin phosphatase targeting subunit-1.

ABSTRACT: Aging causes major alterations of all components of the neurovascular unit and compromises brain blood supply. Here, we tested how aging affects vascular reactivity in basilar arteries from young (<10 weeks; y-BA), old (>22?months; o-BA) and old (>22?months) heterozygous MYPT1-T-696A/+?knock-in mice. In isometrically mounted o-BA, media thickness was increased by ?10% while the passive length tension relations were not altered. Endothelial denudation or pan-NOS inhibition (100?µmol/L L-NAME) increased the basal tone by 11% in y-BA and 23% in o-BA, while inhibition of nNOS (1 µmol/L L-NPA) induced ?10% increase in both ages. eNOS expression was ?2-fold higher in o-BA. In o-BA, U46619-induced force was augmented (pEC₅₀ ?6.9 vs. pEC₅₀ ?6.5) while responsiveness to DEA-NONOate, electrical field stimulation or nicotine was decreased. Basal phosphorylation of MLC₂₀-S19 and MYPT1-T-853 was higher in o-BA and was reversed by apocynin. Furthermore, permeabilized o-BA showed enhanced Ca²⁺-sensitivity. Old T-696A/+?BA displayed a reduced phosphorylation of MYPT1-T696 and MLC₂₀, a lower basal tone in response to L-NAME and a reduced eNOS expression. The results indicate that the vascular hypercontractility found in o-BA is mediated by inhibition of MLCP and is partially compensated by an upregulation of endothelial NO release.

SUBMITTER: Lubomirov LT

PROVIDER: S-EPMC5363478 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Aging-related alterations in eNOS and nNOS responsiveness and smooth muscle reactivity of murine basilar arteries are modulated by apocynin and phosphorylation of myosin phosphatase targeting subunit-1.

Lubomirov Lubomir T LT Papadopoulos Symeon S Pütz Sandra S Welter Johannes J Klöckener Tim T Weckmüller Kathrin K Ardestani Mostafa A MA Filipova Dilyana D Metzler Doris D Metzner Harald H Staszewski Jürgen J Zittrich Stefan S Gagov Hristo H Schroeter Mechthild M MM Pfitzer Gabriele G

Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism 20160720 3

Aging causes major alterations of all components of the neurovascular unit and compromises brain blood supply. Here, we tested how aging affects vascular reactivity in basilar arteries from young (<10 weeks; y-BA), old (>22 months; o-BA) and old (>22 months) heterozygous MYPT1-T-696A/+ knock-in mice. In isometrically mounted o-BA, media thickness was increased by ∼10% while the passive length tension relations were not altered. Endothelial denudation or pan-NOS inhibition (100 µmol/L L-NAME) inc ...[more]

PMID: 27193035

Similar Datasets

Project description:Hyperhomocysteinemia (HHcy) impairs endothelium-dependent vasodilation by increasing reactive oxygen species, thereby reducing nitric oxide (NO.) bioavailability. It is unclear whether reduced expression or function of the enzyme that produces NO., endothelial nitric oxide synthase (eNOS), also contributes. It is also unclear whether resistance vessels that utilize both NO.and non-NO.vasodilatory mechanisms, undergo alteration of non-NO.mechanisms in this condition. We tested these hypotheses in male C57BL/6 mice with chronic HHcy induced by 6-wk high methionine/low-B vitamin feeding (Hcy: 89.2 +/- 49.0 microM) compared with age-matched controls (Hcy: 6.6 +/- 1.9 microM), using first-order mesenteric arteries. Dilation to ACh (10(-9)-10(-4) M) was measured in isolated, cannulated, and pressurized (75 mmHg) arteries with and without N(G)-nitro-l-arginine methyl ester (l-NAME) (10(-4) M) and/or indomethacin (10(-5) M) to test endothelium-dependent dilation and non-NO.-dependent dilation, respectively. The time course of dilation to ACh (10(-4) M) was examined to compare the initial transient dilation due to non-NO., non-prostacyclin mechanism and the sustained dilation due to NO.. These experiments indicated that endothelium-dependent dilation was attenuated (P < 0.05) in HHcy arteries due to downregulation of only NO.-dependent dilation. Western blot analysis indicated significantly less (P < 0.05) basal eNOS and phospho-S1179-eNOS/eNOS in mesenteric arteries from HHcy mice but no difference in phospho-T495-eNOS/eNOS. S1179 eNOS phosphorylation was also significantly less in these arteries when stimulated with ACh ex vivo or in situ. Real-time PCR indicated no difference in eNOS mRNA levels. In conclusion, chronic diet-induced HHcy in mice impairs eNOS protein expression and phosphorylation at S1179, coincident with impaired NO.-dependent dilation, which implicates dysfunction in eNOS post-transcriptional regulation in the impaired endothelium-dependent vasodilation and microvascular disease that is common with HHcy.

Dataset Information

Aging-related alterations in eNOS and nNOS responsiveness and smooth muscle reactivity of murine basilar arteries are modulated by apocynin and phosphorylation of myosin phosphatase targeting subunit-1.

Publications

Aging-related alterations in eNOS and nNOS responsiveness and smooth muscle reactivity of murine basilar arteries are modulated by apocynin and phosphorylation of myosin phosphatase targeting subunit-1.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure