Original scientific paper
https://doi.org/10.3325/cmj.2016.57.223
New insights into coupling and uncoupling of cerebral blood flow and metabolism in the brain
Poornima Venkat
; Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
Michael Chopp
; Department of Physics, Oakland University, Rochester, MI, USA
Jieli Chen
; Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
Abstract
The brain has high metabolic and energy needs and requires
continuous cerebral blood flow (CBF), which is facilitated
by a tight coupling between neuronal activity, CBF,
and metabolism. Upon neuronal activation, there is an increase
in energy demand, which is then met by a hemodynamic
response that increases CBF. Such regional CBF
increase in response to neuronal activation is observed
using neuroimaging techniques such as functional magnetic
resonance imaging and positron emission tomography.
The mechanisms and mediators (eg, nitric oxide, astrocytes,
and ion channels) that regulate CBF-metabolism
coupling have been extensively studied. The neurovascular
unit is a conceptual model encompassing the anatomical
and metabolic interactions between the neurons,
vascular components, and glial cells in the brain. It is compromised
under disease states such as stroke, diabetes, hypertension,
dementias, and with aging, all of which trigger
a cascade of inflammatory responses that exacerbate
brain damage. Hence, tight regulation and maintenance
of neurovascular coupling is central for brain homeostasis.
This review article also discusses the waste clearance pathways
in the brain such as the glymphatic system. The glymphatic
system is a functional waste clearance pathway
that removes metabolic wastes and neurotoxins from the
brain along paravascular channels. Disruption of the glymphatic
system burdens the brain with accumulating waste
and has been reported in aging as well as several neurological
diseases.
Keywords
Hrčak ID:
169599
URI
Publication date:
15.6.2016.
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