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Regulation of cerebral microcirculation--update
1Department of Neurology, School of Medicine, Keio University, Tokyo, Japan.
The Keio Journal of Medicine
|April 6, 2000
Summary
Brain microvasculature control involves neural and chemical pathways. Nitric oxide (NO) is a key mediator in rapid local blood flow increases, crucial for brain function and defense.
Area of Science:
- Neuroscience
- Cerebrovascular Physiology
- Neuroimmunology
Background:
- Explores neural and chemical control of brain microvasculature.
- Focuses on rapid blood flow responses to stimuli.
- Investigates extrinsic and intrinsic neural pathways influencing cerebral blood flow.
Framework:
- Vasoactive intestinal polypeptide (VIP)-containing parasympathetic nerves exhibit neurokinin-1 receptors activated by substance P.
- Cholinergic fibers from basal forebrain nuclei may use nitric oxide (NO) as a relay for flow activation.
- NMDA receptors and ATP-sensitive potassium channels form a vasodilating system.
Implementation:
- Substance P activates neurokinin-1 receptors on parasympathetic nerves, potentially increasing local flow.
- Intrinsic neurons release NO, mediating flow responses initiated by cholinergic pathways.
- Hypoxia and ischemia disrupt vasodilating systems via cyclooxygenase-derived superoxide anion.
Implications:
- Identifies NO as a common mediator for rapid microvascular flow increases in the brain.
- Suggests a defensive role for neurokinin-1 receptor activation in the brain.
- Highlights the disruption of cerebrovascular regulation during ischemic events.