Acetylcholine

Unlike dopamine, there is an increase in acetylcholine in Parkinson's disease. This neurotransmitter is synthesized in the basal nucleus of Meynert (basal forebrain). In the autonomic nervous system, it serves as the neurotransmitter for sweat glands and adrenal medulla. In the peripheral nervous system, acetylcholine plays a role in skeletal muscle activation, specifically between the motor nerve and skeletal muscle. In the central nervous system it is involved in alertness, attention, and learning. Acetylcholine receptors are classified as either nicotinic or muscarinic.

Other disorders involving acetylcholine include Myasthenia gravis and Alzheimer's disease.

1. Myasthenia gravis
In Myasthenia gravis, the body produces antibodies against acetylcholine nicotinic receptors, inhibiting proper acetylcholine signal transduction. As a result, the patient suffers from weakness and fatigue.

2. Alzheimer's disease
In Alzheimer's disease, plaques are formed in the brain. The plaque lead to cell death and decreased levels of the acetylcholine in the cerebral cortex and caudate nucleus. Treatment of Alzheimer's include acetylcholinesterase inhibitors, which prevent the breakdown of acetylcholine to make up for the lack of neurotransmitter.