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Free Radic Biol Med. 2014 Aug;73:421-9. doi: 10.1016/j.freeradbiomed.2014.05.021. Epub 2014 Jun 2.

Neurovascular coupling in hippocampus is mediated via diffusion by neuronal-derived nitric oxide.

Author information

1
Faculty of Pharmacy and Center for Neurosciences and Cell Biology, University of Coimbra, Health Sciences Campus, 3000-548 Coimbra, Portugal.
2
Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA.
3
Department of Biochemistry and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la Republica, Montevideo, Uruguay.
4
Faculty of Pharmacy and Center for Neurosciences and Cell Biology, University of Coimbra, Health Sciences Campus, 3000-548 Coimbra, Portugal. Electronic address: laranjin@ci.uc.pt.

Abstract

The coupling between neuronal activity and cerebral blood flow (CBF) is essential for normal brain function. The mechanisms behind this neurovascular coupling process remain elusive, mainly because of difficulties in probing dynamically the functional and coordinated interaction between neurons and the vasculature in vivo. Direct and simultaneous measurements of nitric oxide (NO) dynamics and CBF changes in hippocampus in vivo support the notion that during glutamatergic activation nNOS-derived NO induces a time-, space-, and amplitude-coupled increase in the local CBF, later followed by a transient increase in local O2 tension. These events are dependent on the activation of the NMDA-glutamate receptor and nNOS, without a significant contribution of endothelial-derived NO or astrocyte-neuron signaling pathways. Upon diffusion of NO from active neurons, the vascular response encompasses the activation of soluble guanylate cyclase. Hence, in the hippocampus, neurovascular coupling is mediated by nNOS-derived NO via a diffusional connection between active glutamatergic neurons and blood vessels.

KEYWORDS:

Brain; Free radicals; Functional hyperemia; Hippocampus; Neurons; Neurovascular coupling; Nitric oxide

[Indexed for MEDLINE]

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