Functional hyperemia in the brain

Hypothesis for astrocyte-derived vasodilator metabolites

David R. Harder, Nabil Alkayed, Andrew R. Lange, Debebe Gebremedhin, Richard J. Roman

Research output: Contribution to journalArticle

174 Citations (Scopus)

Abstract

Background - Cerebral blood flow is tightly coupled to neuronal metabolic activity, a phenomenon referred to as functional hyperemia. The mechanisms underlying functional hyperemia in the brain have been extensively studied, but the link between neuronal activation and nutritive blood flow has yet to be defined. Recent investigations by our laboratory and others have identified a potential role for astrocytes as an intermediary cell type in this process. Summary of Review - This short review will develop the hypothesis that cytochrome P450 epoxygenase activity in astrocytes catalyzes formation of epoxyeicosatrienoic acids (EETs), which act as potent dilators of cerebral vessels and are released in response to glutamate receptor activation within astrocytes. Neuronal activity stimulates release of arachidonic acid from the phospholipid pool of astrocytic membranes. We provide evidence that the arachidonic acid released on stimulation of glutamate receptors within astrocytes is metabolized by cytochrome P450 2C11 cDNA enzymes into EETs. Conclusions - The EETs thus formed will be released and activate K+ channels, increase outward K+ current, and hyperpolarize the plasma membrane. The resulting membrane hyperpolarization inhibits voltage-gated Ca2+ channels and leads to arteriolar dilation, thereby increasing regional nutritive blood flow in response to neuronal activity.

Original languageEnglish (US)
Pages (from-to)229-234
Number of pages6
JournalStroke
Volume29
Issue number1
StatePublished - Jan 1998
Externally publishedYes

Fingerprint

Hyperemia
Vasodilator Agents
Astrocytes
Glutamate Receptors
Brain
Arachidonic Acid
Cytochrome P-450 Enzyme System
Cerebrovascular Circulation
Membranes
Regional Blood Flow
Dilatation
Phospholipids
Complementary DNA
Cell Membrane
Acids
Enzymes

Keywords

  • Astrocytes
  • Blood flow
  • Vasodilation

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Neuroscience(all)

Cite this

Harder, D. R., Alkayed, N., Lange, A. R., Gebremedhin, D., & Roman, R. J. (1998). Functional hyperemia in the brain: Hypothesis for astrocyte-derived vasodilator metabolites. Stroke, 29(1), 229-234.

Functional hyperemia in the brain : Hypothesis for astrocyte-derived vasodilator metabolites. / Harder, David R.; Alkayed, Nabil; Lange, Andrew R.; Gebremedhin, Debebe; Roman, Richard J.

In: Stroke, Vol. 29, No. 1, 01.1998, p. 229-234.

Research output: Contribution to journalArticle

Harder, DR, Alkayed, N, Lange, AR, Gebremedhin, D & Roman, RJ 1998, 'Functional hyperemia in the brain: Hypothesis for astrocyte-derived vasodilator metabolites', Stroke, vol. 29, no. 1, pp. 229-234.
Harder DR, Alkayed N, Lange AR, Gebremedhin D, Roman RJ. Functional hyperemia in the brain: Hypothesis for astrocyte-derived vasodilator metabolites. Stroke. 1998 Jan;29(1):229-234.
Harder, David R. ; Alkayed, Nabil ; Lange, Andrew R. ; Gebremedhin, Debebe ; Roman, Richard J. / Functional hyperemia in the brain : Hypothesis for astrocyte-derived vasodilator metabolites. In: Stroke. 1998 ; Vol. 29, No. 1. pp. 229-234.
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