Cholinesterase is a family of enzymes that catalyzes the hydrolysis of the neurotransmitter acetylcholine (ACh) into choline and acetic acid, a reaction necessary to allow a cholinergic neuron to return to its resting state after activation.
What is acetylcholinesterase also known as?
Acetylcholinesterase (HGNC symbol ACHE; EC 3.1. 1.7), also known as AChE or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme that catalyzes the breakdown of acetylcholine and of some other choline esters that function as neurotransmitters.
Where does cholinesterase come from?
Cholinesterase is a plasma enzyme, produced by the liver, which is capable of hydrolysing a variety of choline esters. Plasma activity falls with decreased protein synthesis in liver disease.
How many types of cholinesterase are there?
There are two types: acetylcholinesterase (AChE, EC 3.1. 1.7) and pseudocholinesterase (BChE, EC 3.1. 1.8). AChE was found primarily in the blood on red blood cell membranes, in neuromuscular junctions, and in neural synapses while it is produced in the liver and found primarily in plasma .
What is the normal cholinesterase level?
Typically, normal pseudocholinesterase values range between 8 and 18 units per milliliter (U/mL) or 8 and 18 kilounits per liter (kU/L). Note: Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.
What happens if acetylcholinesterase is not present?
If acetylcholinesterase activity is inhibited, the synaptic concentration of acetylcholine will remain higher than normal. If this inhibition is irreversible, as in the case of exposure to many nerve gases and some pesticides, sweating, bronchial constriction, convulsions, paralysis, and possibly death can occur.
What happens if cholinesterase is low?
People who have low levels or defective pseudocholinesterase may experience prolonged effects of the drug, with protracted muscle paralysis and apnea following anesthesia. In addition, those who are homozygous for genetic variants may be at greater risk of adverse effects than those who are heterozygous.
What are the anticholinesterase drugs?
Anticholinesterases are drugs that prolong the existence of acetylcholine after it is released from cholinergic nerve endings by inhibiting both acetylcholinesterase and butyrylcholinesterase. They are two types: prosthetic and acid-transferring.
What are the side effects of cholinesterase inhibitors?
The most common adverse effects of cholinesterase inhibitors include nausea, diarrhea, vomiting, decreased appetite, dyspepsia, anorexia, muscle cramps, fatigue, insomnia, dizziness, headache, and asthenia. 1–3 Taking these medications with food, preferably a full meal, can mitigate these gastrointestinal effects.
Are cholinesterase medications expensive?
Cholinesterase inhibitors may also influence behavioural and psychological symptoms in Alzheimer’s disease. Cholinesterase inhibitors are also regarded as rather expensive and, therefore, the question of cost effectiveness is essential.
What do cholinesterase inhibitors treat?
The main use of cholinesterase inhibitors is for the treatment of dementia in patients with Alzheimer’s disease. People with Alzheimer’s disease have reduced levels of acetylcholine in the brain. Cholinesterase inhibitors have been shown to have a modest effect on dementia symptoms such as cognition.
What is meant by acetylcholine?
Acetylcholine is the chief neurotransmitter of the parasympathetic nervous system, the part of the autonomic nervous system (a branch of the peripheral nervous system) that contracts smooth muscles, dilates blood vessels, increases bodily secretions, and slows heart rate.
What drugs are metabolized by Pseudocholinesterase?
Neuromuscular Blocking Drugs
Butyrylcholinesterase (BChE) or pseudocholinesterase is the enzyme that hydrolyzes neuromuscular blocking agents such as succinylcholine and mivacurium, as well as ester local anesthetic agents.
Is cholinesterase deficiency hereditary?
Acquired pseudocholinesterase deficiency is not inherited and cannot be passed to the next generation. This form of the condition is caused by impairment of the enzyme’s function due to factors such as kidney or liver disease, malnutrition, major burns, cancer , or certain drugs.
What drugs should be avoided with pseudocholinesterase deficiency?
The use of succinylcholine, mivacurium and ester local anesthetics must be avoided in patients with pseudocholinesterase deficiency because these patients may not be able to metabolize such anesthetics.
How do you know if you have pseudocholinesterase deficiency?
Pseudocholinesterase deficiency may be suspected when you have problems recovering muscle control and breathing after receiving the muscle relaxant succinylcholine or mivacurium as part of anesthesia. A blood test can be done to measure pseudocholinesterase enzyme activity.
What triggers acetylcholinesterase?
Acetylcholinesterase in Action
Acetylcholinesterase is found in the synapse between nerve cells and muscle cells. It waits patiently and springs into action soon after a signal is passed, breaking down the acetylcholine into its two component parts, acetic acid and choline.
What happens if there is too much acetylcholinesterase?
Excessive accumulation of acetylcholine (ACh) at the neuromuscular junctions and synapses causes symptoms of both muscarinic and nicotinic toxicity. These include cramps, increased salivation, lacrimation, muscular weakness, paralysis, muscular fasciculation, diarrhea, and blurry vision.
Which is the common neurotransmitter in brain?
The most common neurotransmitter in the CNS is glutamate, present in more than 80% of synapses in the brain. Gamma-aminobutyric acid (GABA) is present in the majority of other synapses.
What do high cholinesterase levels mean?
A high level of cholinesterase in the blood may be related to multiple diseases such as diabetes, hyperlipidemia, a high cholesterol level, hypertension, etc. If values are very high, it may be a sign of nephrotic syndrome.
When should a blood test for baseline cholinesterase be done?
When obtaining the 2nd baseline, wait to test until at least 3 days after the baseline, but within 30 days and ensure no pesticide exposures during this time period. Measure both acetylcholinesterase (red blood cell cholinesterase-AChE) and butyryl cholin- esterase (plasma cholinesterase-PChE).
Is there a blood test for choline levels?
At present, there is no definitive clinical test that can be used to identify persons who are choline deficient. Plasma choline, betaine, and phosphatidylcholine concentrations decreased in humans fed a choline-deficient diet, but they plateau after falling 30%–50% (2, 24).