Search results
Results From The WOW.Com Content Network
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]
While he initially attributed this effect to choline, he later discovered acetylcholine was 100 000 times more potent in lowering blood pressure. [2] Sir Henry Hallett Dale. British physiologist Sir Henry Hallett Dale (1875-1968) observed acetylcholine for causing blood vessel dilation and slowing down heart rate. In 1914, Dale noted that the ...
Drugs with muscarinic antagonist activity are widely used in medicine, in the treatment of low heart rate, overactive bladder, respiratory problems such as asthma and chronic obstructive pulmonary disease (COPD), and neurological problems such as Parkinson's disease and Alzheimer's disease.
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.
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.
Beta blockers with greater blood–brain barrier permeability can have both neuropsychiatric therapeutic benefits and side effects, as well as adverse cognitive effects. [76] Central nervous system-related side effects and risks of beta blockers may include fatigue , depression , sleep disorders (namely insomnia ) and nightmares , visual ...
A parasympathomimetic drug, sometimes called a cholinomimetic drug [1] or cholinergic receptor stimulating agent, [2] is a substance that stimulates the parasympathetic nervous system (PSNS). [ 3 ] [ 2 ] These chemicals are also called cholinergic drugs because acetylcholine (ACh) is the neurotransmitter used by the PSNS.