There are more than 100 neurotransmitters that have been identified in the body over the years but no one knows how many neurotransmitters exist in humans and other organisms. Neurotransmitters are chemical substances that carry messages across the synaptic space to other neurons, muscles or glands. They are fundamental to behaviour, playing a key role in everything from muscle movement to moods and mental health (Weiten, 2010). In this essay the author will be looking at one particular neurotransmitter called acetylcholine abbreviated as ACh, its psychobehavioural role and the effects of psychoactive drugs that support its role.
In the Millodot: Dictionary of Optometry and Visual Science, 2009, para. 1; defines acetylcholine as a neurotransmitter substance with special excitatory properties of all preganglionic autonomic neurons, all parasympathetic postganglionic neurons and a few postganglionic sympathetic neurons. ACh is synthesized and liberated by the action of the enzyme choline acetyltranferase from the compounds choline and acetyl coenzyme A (acetyl CoA) which occurs in all cholinergic neurons. ACh exists only momentarily after its formation, being hydrolysed by the enzyme acetylcholinesterase which is present in the neurons of cholinergic nerves throughout their entire lengths and at neuromuscular junctions, this process is important for proper muscle function as otherwise the accumulation of ACh would result in continuous stimulation of the muscles, glands and central nervous system. Alternatively a shortage of ACh has devastating effect for example myasthenia gravis. ACh binds to acetylcholine receptors on skeletal muscle fibres. Sodium enters the muscle fibre membrane, which leads to a depolarization of the membrane and muscle contraction. Psychoactive drugs can be defined as the drugs that can produce mood changes and distorted perceptions or as a chemical that alters brain function, resulting in temporary changes in perception, mood,...