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Symptoms are thought to arise from transient abnormalities in the blood vessels of the brain. [1] In some cases, it may be associated with childbirth, vasoactive or illicit drug use, or complications of pregnancy. [1] If it occurs after delivery it may be referred to as postpartum cerebral angiopathy.
The narrowing of blood vessels leads to an increase in peripheral resistance, thereby elevating blood pressure. While vasoconstriction is a normal and essential regulatory mechanism for maintaining blood pressure and redistributing blood flow during various physiological processes, its dysregulation can contribute to pathological conditions.
It causes vasoconstriction in many blood vessels, including those of the skin, gastrointestinal system, kidney (renal artery) [16] and brain. [17] Other areas of smooth muscle contraction are: ureter; vas deferens; hair (arrector pili muscles) uterus (when pregnant) urethral sphincter; urothelium and lamina propria [18]
At issue is what’s called the blood-brain barrier, a protective lining in blood vessels that prevents germs and other damaging substances from Alzheimer's drugs might get into the brain faster ...
Moyamoya disease is a disease in which certain arteries in the brain are constricted. Blood flow is blocked by constriction and blood clots (). [2]A collateral circulation develops around the blocked vessels to compensate for the blockage, but the collateral vessels are small, weak, and prone to bleeding, aneurysm and thrombosis.
Cerebral blood flow (CBF) is the blood supply to the brain in a given period of time. [8] In an adult, CBF is typically 750 millilitres per minute or 15.8 ± 5.7% of the cardiac output. [9] This equates to an average perfusion of 50 to 54 millilitres of blood per 100 grams of brain tissue per minute. [10] [11] [12]
The blood–brain barrier is formed by special tight junctions between endothelial cells lining brain blood vessels. Blood vessels of all tissues contain this monolayer of endothelial cells, however only brain endothelial cells have tight junctions preventing passive diffusion of most substances into the brain tissue. [1]
Sympathomimetic drugs are used to treat cardiac arrest and low blood pressure, or even delay premature labor, among other things. These drugs can act through several mechanisms, such as directly activating postsynaptic receptors, blocking breakdown and reuptake of certain neurotransmitters, or stimulating production and release of catecholamines.