Abstract
Background The human brain, depending on aerobic glycolysis to cover its metabolic needs and
having no energy reserves whatsoever, relies on a constant and closely regulated blood
supply to maintain its structural and functional integrity. Cerebral autoregulation,
that is, the brain's intrinsic ability to regulate its own blood flow independently
from the systemic blood pressure and cardiac output, is an important physiological
mechanism that offers protection from hypoperfusion injury.
Discussion Two major independent mechanisms are known to be involved in cerebral autoregulation:
(1) flow–metabolism coupling and (2) myogenic responses of cerebral blood vessels
to changes in transmural/arterial pressure. A third, less prominent component of cerebral
autoregulation comes in the form of neurogenic influences on cerebral vasculature.
Conclusion Although fragmentation of cerebral autoregulation in separate and distinct from each
other mechanisms is somewhat arbitrary, such a scheme is useful for reasons of simplification
and to better understand their overall effect. Comprehension of cerebral autoregulation
is imperative for clinicians in order for them to mitigate consequences of its impairment
in the context of traumatic brain injury, subarachnoid hemorrhage, stroke, or other
pathological conditions.
Keywords
cerebral autoregulation - cerebral blood flow - flow–metabolism coupling
