A study of acetylcholinesterase and its inhibition - Essay Example

The purpose of this study was to explore the enzyme acetylcholinesterase and the physiology of this complex system, and the various disorders associated with the cholinergic system by a review of literature. The central nervous system (CNS) gets a variety of internal and external stimuli. These are integrated and expressed subconsciously through the autonomic nervous system, which modulates the involuntary functions of the body. The autonomic nervous system is divided into the sympathetic (thoracolumbar) outflow, and the parasympathetic (craniosacral) outflow (Robertson D, 2005.) Neurotransmitters are chemical substances that help neurons to communicate with other neurons through a chemical synapse.

They are categorized into four groups: monoamines, amino acids, peptides and acetylcholine. After synthesis, they are packaged and transported, if required, to the presynaptic cell terminal. The release of the neurotransmitter into the synaptic cleft is triggered by the arrival of an action potential at the presynaptic cell terminal. The neurotransmitter then diffuses across the synapse, and activates receptors on the postsynaptic cell resulting in either excitation or inhibition of that cell.

The final step in this process is the inactivation of the neurotransmitter by enzymatic breakdown, re-uptake or by neurotransmitter diffusion. (PKAL conference, 1997.) Acetylcholine (ACh) is the primary neuromediator of both sympathetic and parasympathetic preganglionic neurons. It is also the mediator of parasympathetic postganglionic fibres. ACh has mostly an excitatory effect but it is known to have inhibitory effects at some of the peripheral parasympathetic nerve endings, like inhibition of the heart by the vagus nerve (Guyton AC, 1986.) Myasthenia gravis is an autoimmune disease due to the lack of cholinergic receptors in the peripheral nervous system (PNS).

Although the function of ACh in the brain is not as