IngentaConnect Temporal Dynamics of Brain Tissue Nitric Oxide during Functional ...

Authors: Buerk D.G.¹; Ances B.M.²; Greenberg J.H.^{2, 3}; Detre J.A.^{2, 3}

Source: NeuroImage, Volume 18, Number 1, January 2003 , pp. 1-9(9)

Abstract:

We report the first dynamic measurements of tissue nitric oxide (NO) during functional activation of rat somatosensory cortex by electrical forepaw stimulation. Cortical tissue NO was measured electrochemically with rapid-responding recessed microelectrodes (tips <10 m). Simultaneous blood flow measurements were made by laser–Doppler flowmetry (LDF). NO immediately increased, reaching a peak 125.5 ± 32.8 (SE) nM above baseline (P < 0.05) within 400 ms after stimulus onset, preceding any LDF changes, and then returned close to prestimulus levels after 2 s (123 signal-averaged trials, 12 rats). Blood flow began rising after a 1-s delay, reaching a peak just before electrical stimulation was ended at t = 4 s. A consistent poststimulus NO undershoot was observed as LDF returned to baseline. These findings complement our previous study (B. M. Ances et al., 2001, Neurosci. Lett. 306, 106–110) in which a transient decrease in rat somatosensory cortex tissue oxygen partial pressure was found to precede blood flow increases during functional activation. ©2002 Elsevier Science (USA).

Keywords: cerebral blood flow; functional activation; laser–; Doppler flowmetry; nitric oxide; nitric oxide synthase; nitric oxide microelectrode

Language: English

Document Type: Research article

DOI: 10.1006/nimg.2002.1314

Affiliations: 1: Department of Bioengineering, Institute for Environmental Medicine 2: Department of Bioengineering, Institute for Environmental Medicine, Department of Neurology 3: Department of Bioengineering, Institute for Environmental Medicine, Department of Neurology, Cerebrovascular Research Center, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, 19104

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Temporal Dynamics of Brain Tissue Nitric Oxide during Functional Forepaw Stimulation in Rats