Acetylcholine (ACh) is an important neurotransmitter in the body that communicates signals to neurons within the body. An examination of the workings of ACh at the molecular level will reveal the interplay of neurons. From the molecular chemistry and the neuronal interplay of ACh, the inhibitors and drugs related to it can be comprehended.
Neurotransmitters are chemicals that carry messages to the brain via neural communication. Specifically, ACh is an important neurotransmitter used for memory and muscle movement. Whenever neurons send messages, the nerve excites and creates an action potential, which creates a rush of sodium and a positive charge. Then, the neurotransmitter gets sent to the synaptic gap between the axon terminals of the sending neuron and the dendrite of the receiving neuron. The dendrites receive the neurotransmitter. This process is repeated by sensory neurons, interneurons, and motor neurons to tell the body what to do.
Figure 1: Visual representation of neural transmission
The chemical structure of ACh is C7NH16O2+. The enzyme that breaks down ACh, acetylcholinesterase, rapidly hydrolyzes ACh into choline and acetal. In essence, the substrate (ACh) and water (H2O) react to form choline and acetate, which then cleaves to the receptor of the receiving neuron. In the active site of this enzyme, an important mechanism is performed by a catalytic triad in order for the reaction to be performed. This catalytic triad consists of serine (nucleophile), histidine (base), and glutamate (activator).
Figure 2: catalytic triad of ACh and the reaction
Inhibitors are molecules that can block the active site and alter the amount of substrate concentration needed to bind to the enzyme. As a result, acetylcholine builds up in the cell, which can cause muscle spasms and uncontrollable muscle movement. However, inhibitors of acetylcholinesterase can be beneficial. Drugs such as donepezil and galantamine are used to treat Alzheimer’s disease by blocking the active site of acetylcholinesterase and causing ACh to buildup. Thus, with a higher concentration of the neurotransmitter in the brain, memory enhances.
Acetylcholine has many functions in the body, but it is mainly a neurotransmitter that tells the brain to contract muscles and is useful for memory. The hydrolyzation of ACh using acetylcholinesterase and the catalytic triad is a sophisticated reaction that shows the process of the neurotransmitter when it flows from one neuron to another. Inhibitors of this process cause ACh buildup. As a result of an excess of ACh, muscle spasms may occur. On the other hand, it may boost neuronal pathways in the brain and improve memory. At last, acetylcholine is still being researched and is essential to the discovery of the cure to Alzheimer’s disease.
Works Cited
Alzheimer's Society. 2020. How Do Drugs For Alzheimer's Disease Work?. [online] Available at: <https://www.alzheimers.org.uk/about-dementia/treatments/drugs/how-do-drugs-alzheimers-disease-work#:~:text=Donepezil%2C%20rivastigmine%20and%20galantamine%20all,Alzheimer's%20disease%20for%20a%20while.> [Accessed 20 July 2020].
Figure 1, Qbi.uq.edu.au. 2020. How Do Neurons Work?. [online] Available at: <https://qbi.uq.edu.au/brain-basics/brain/brain-physiology/how-do-neurons-work> [Accessed 20 July 2020].
Figure 2, Abdelazim, K., 2020. Amino Acids And Proteins/ Cholinesterase Enzyme.