Cerebral Blood Flow Regulation by Nitric Oxide in Alzheimer's Disease

2012 ◽  
Vol 32 (3) ◽  
pp. 569-578 ◽  
Author(s):  
Noboru Toda ◽  
Tomio Okamura
2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S91-S91
Author(s):  
Candice E Van Skike ◽  
Stacy A Hussong ◽  
Andy Banh ◽  
Veronica Galvan

Abstract We recently identified pathogenic soluble aggregated tau (tau oligomers) in the cerebral microvasculature of human patients with tauopathies, including Alzheimer’s disease (AD). The functional consequences of cerebrovascular tau accumulation are not yet understood. The aim of the present study was to determine whether pathogenic tau accumulation leads to cerebrovascular dysfunction. To this end, we measured neurovascular coupling (NVC), a highly regulated process that synchronizes cerebral blood flow to neuronal activation, using the PS19(P301S) mouse model of tauopathy. The change in cerebral blood flow evoked by whisker stimulation was measured using Laser Doppler flowmetry in PS19 and wildtype control mice and the functional contribution of neuronal and endothelial nitric oxide synthase (nNOS and eNOS, respectively) was calculated. Vascular reactivity was assessed using topical acetylcholine to evoke endothelium-dependent vasodilation. To assess the direct impact of pathogenic tau on cell-specific NOS function, we treated N2a neuroblastoma cells or mouse brain vascular endothelial cells with soluble tau aggregates and measured activity of nNOS and eNOS. Our data indicate isolated overexpression of mutant tau impairs NVC responses, and this deficit is mediated by a reduction in nNOS activity in vivo. Further, our studies suggest tauopathy also impairs endothelium-dependent vasoreactivity in the cortex. Additionally, soluble tau aggregates inhibit the phosphorylation of NOS in primary cultured cells. Therefore, inhibition of NOS phosphorylation by pathogenic soluble tau aggregates may underlie cerebrovascular dysfunction in tauopathies. Thus, therapeutic modulation of pathogenic tau may mitigate brain microvascular deficits, which occur prior to clinical onset in Alzheimer’s disease and potentially other tauopathies.


2010 ◽  
Vol 60 (6) ◽  
pp. 399-406 ◽  
Author(s):  
Hiroyuki Takuwa ◽  
Tetsuya Matsuura ◽  
Rumiana Bakalova ◽  
Takayuki Obata ◽  
Iwao Kanno

2009 ◽  
Vol 61 (1) ◽  
pp. 62-97 ◽  
Author(s):  
Noboru Toda ◽  
Kazuhide Ayajiki ◽  
Tomio Okamura

2009 ◽  
Vol 87 (8) ◽  
pp. 581-594 ◽  
Author(s):  
Noboru Toda ◽  
Kazuhide Ayajiki ◽  
Tomio Okamura

There has been a rapid increase in the amount of information on the physiological and pathophysiological roles of nitric oxide (NO) in the brain. This molecule, which is formed by the constitutive isoforms of NO synthase, endothelial (eNOS) and neuronal (nNOS), plays an obligatory role in the regulation of cerebral blood flow and cell viability and in the protection of nerve cells or fibres against pathogenic factors associated with Alzheimer’s disease, Huntington’s disease, seizures, and migraine. Cerebral blood flow is impaired by decreased formation of NO from endothelial cells, autonomic nitrergic nerves, or brain neurons and also by increased production of reactive oxygen species (ROS). The NO–ROS interaction is an important topic in discussing blood flow and cell viability in the brain. Excessive production of NO by inducible NOS (iNOS) and nNOS in the brain participates in neurotoxicity. Recent studies on brain circulation have provided useful information about the involvement of impaired NO availability or uncontrolled NO production in cerebral pathogenesis, including Alzheimer’s disease, seizures, vascular headaches, and inflammatory disorders. Insight into the role of NO in the brain will contribute to our better understanding of cerebral hemodynamic dysfunction and will aid in developing novel therapeutic measures in diseases of the central nervous system.


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