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Proc Natl Acad Sci U S A. 2008 Jan 22;105(3):1073-8. doi: 10.1073/pnas.0708823105. Epub 2008 Jan 14.

Key role of tissue plasminogen activator in neurovascular coupling.

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  • 1Division of Neurobiology, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10021, USA.


The increase in blood flow evoked by synaptic activity is essential for normal brain function and underlies functional brain imaging signals. Nitric oxide, a vasodilator released by NMDA receptor activation, is critical for the flow increase, but the factors linking NMDA receptor activity to nitric oxide-dependent hyperemia are poorly understood. Here, we show that tissue plasminogen activator (tPA), a serine protease implicated in NMDA receptor signaling, is required for the flow increase evoked by somatosensory stimulation. tPA acts by facilitating neuronal nitric oxide release, but this effect does not involve enhancement of NMDA currents or the associated intracellular Ca(2+) rise. Rather, the evidence suggests that tPA controls NMDA-dependent nitric oxide synthesis by influencing the phosphorylation state of neuronal nitric oxide synthase. These findings unveil a previously unrecognized role of tPA in vital homeostatic mechanisms coupling NMDA receptor signaling with nitric oxide synthesis and local cerebral perfusion.

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