Neuroeffector junction cholinergic

There are two major types of cholinesterases acetylcholinesterase (AChE) and pseudocholinesterase (pseudo-ChE). AChE (also known as true, specific, or erythrocyte cholinesterase) is found at a number of sites in the body, the most important being the cholinergic neuroeffector junction. Here it is localized to the prejunctional and postjunctional membranes, where it rapidly terminates the action of synaptically released ACh. It is essential to recognize that the action of ACh is ter-... 

Carbamates effect the reversible carbamylation of acetylcholinesterase, permitting accumulation of acetylcholine at cholinergic neuroeffector junctions (muscarinic effects), at the myoneural junctions of skeletal muscle, and in the autonomic ganglia (nicotinic effects). CNS function is also impaired. However the relatively large dissociation constant of the carbamyl-enzyme complex indicates that it dissociates more readily than does the organophosphate-enzyme complex, mitigating the toxicity of the carbamate pesticides. The reversibility of the carbamyl-enzyme complex affects (limits) the utility of blood enzyme measurements as a diagnostic tool. 

The primary mechanism used by cholinergic synapses is enzymatic degradation. Acetylcholinesterase hydrolyzes acetylcholine to its components choline and acetate it is one of the fastest acting enzymes in the body and acetylcholine removal occurs in less than 1 msec. The most important mechanism for removal of norepinephrine from the neuroeffector junction is the reuptake of this neurotransmitter into the sympathetic neuron that released it. Norepinephrine may then be metabolized intraneuronally by monoamine oxidase (MAO). The circulating catecholamines — epinephrine and norepinephrine — are inactivated by catechol-O-methyltransferase (COMT) in the liver. 

Unlike the receptors at postganglionic neuroeffector junctions or at skeletal neuromuscular junctions, both types of cholinergic receptors, that is, nicotinic and mus-... 

Acetylcholine is the endogenous neurotransmitter at cholinergic synapses and neuroeffector junctions in the central and peripheral nervous systems. The actions of acetylcholine are mediated through nicotinic and muscarinic cholinergic receptors, which transduce signals via distinct mechanisms. 

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