Acetylcholine

Overview

Acetylcholine, ACh, is a type of neurotransmitter, cholinergic neurons, and the most abundant neurotransmitter in the brain. Synthesis of acetylcholine is produced by the enzyme, choline acetyltransferase, by combining choline with acetate from acetyl coenzyme (CoA). Acetylcholine is also produced in the intestines.

Biological Functions of Acetylcholine

Nerve Fibers that release Acetylcholine are described as Cholinergic. Acetylcholine is involved in learning, memory, and mood. 

Digestive System

 Acetylcholine is produced in the Intestines where its function is to enhance the process of , thereby helping to prevent Constipation.  ^[1]

Metabolism

 It has been hypothesized that Acetylcholine malfunction (especially in its relationship with Nicotinic Receptors) may be an underlying cause of Chronic Fatigue Syndrome (CFS).  The rationale is that Acetylcholine malfunction in the Peripheral Nervous System may account for the physical (muscle) Fatigue experienced by CFS patients and that Acetylcholine malfunction in the Central Nervous System may account for the mental Fatigue experienced by CFS patients.  ^[2]

  Insufficient release of Acetylcholine at the Neuromuscular Junction is an underlying cause of many cases of (muscular) Fatigue.  ^[3]

Musculoskeletal System

 Acetylcholine is responsible for stimulating Muscles to move:

 Neuromuscular Junctions at the end of Motor Nerves conduct the release of Acetylcholine from the Axons of Motor Nerves to their target Muscle Fibers and via this process Acetylcholine facilitates the movement of Muscles.

 Acetylcholine ensures that Mucous Membranes remain lubricated and moist.  ^[4]

 Acetylcholine is required for optimal Muscle Tone.  ^[5]

Nervous System

 Acetylcholine may increase Alertness.

 Acetylcholine deficiency is implicated in Alzheimer''s Disease.  ^[6]

 Acetylcholine may increase Attention Span.  ^[7]

 Acetylcholine controls the Parasympathetic Nervous System a component of the Autonomic Nervous System.

 Acetylcholine is widely distributed within the Brain.The highest concentrations of Brain Acetylcholine are found in these areas of the Brain:

 Basal Ganglia (Acetylcholine persists within the Basal Ganglia even after Dopaminergic Neurons degenerate in the case of Parkinson''s Disease).

 Caudate Nucleus an important part of the brain''s learning and memory system.

 Certain Brain Stem Nuclei

 Cerebral Cortex - primarily the Frontal Lobe.

 Motor Neurons

  Acetylcholine may improve Concentration ability.  ^[8]

 Acetylcholine is responsible for Coordination.

 Acetylcholine deficiency may cause Dementia.

 Acetylcholine deficiency is implicated in Depression.

 Acetylcholine concentrates in the Hippocampus of the Brain.

 Acetylcholine deficiency is implicated in Huntington''s Disease.

 Optimal Acetylcholine levels enhance various aspects of Intelligence.  ^[9]

 Acetylcholine is involved in Learning.  ^[10]

 Acetylcholine relays the Nerve Impulses that are involved in Memory and Acetylcholine deficiency has been implicated in Memory loss.  ^[11]

 Acetylcholine increases Motivation.

 Acetylcholine helps to maintain Sleep.  It controls the amount of sensory input that reaches the Brain during Sleep and increases the stimulus barrier (increasing the threshold of sensory inputs before wakiing occurs) during Sleep.  Optimal Acetylcholine allows sleepers to remain asleep through minor noises and other disturbances.  Light sleepers are likely to have sub-optimal Acetylcholine:  ^[12]

      Acetylcholine appears to govern Sleep - Rapid Eye Movement (REM) Sleep.  ^[13]

 Tardive Dyskinesia patients exhibit low Acetylcholine levels.

Sexual System

 Decreased Sexual Desire in persons aged 40 and over is partly due to low Acetylcholine levels (and increased Acetylcholine levels in people aged 40 and over can result in increased Sexual Desire).  ^[14]

  Acetylcholine is involved in some aspects of Sexual Performance:  ^[15]

      In males, Acetylcholine plays a role in the Corpus Cavernosum of the Penis essential for attaining erections.

Acetylcholine Enhances the Function of these Substances