Question

Identify the pathophysiology of various neurotransmitters associated with mood disorder?

Answer 1

Neurotransmitters

Any substance, such as acetylcholine or dopamine, responsible for sending nerve signals across a synapse between two neurons is called a neurotransmitter.

Mood disorders( affective disorders) are a group of disorders characterised by the extreme changes in the mood from elevated mood( mania) to extreme sadness( depression). The main mood disorders are mania, depression and bipolar mood disorders.

Pathophysiology of mood disorders

The neurotransmitters , mainly involved in the pathophysiology of mood disorders are dopamine,serotonin and norepinephrine.

Depression

Decreased level of serotonin, norepinephrine and dopamine may result in low mood ranging from sadness to depression. Serotonin is responsible for the regulation of sleep, appetite and activness. Dopamine regulates the reward motivated behaviour. If the dopamine is less then person will not have the initiation of activity or goal oriented activity.

Decreased level of serotonin and dopamine may be due to decreased production of these neurotransmitters in brain or the increased activity of Monoamine Oxidase enzyme in brain. This enzyme is responsible for degradation of Monoamine neurotransmitters( serotonin,dopamine) thus decreases its level in the brain.

Mania

Increased levels of dopamine and norepinephrine causes mania , ranging from euphoria to ecstasy. These neurotransmitters activities will be increasesd during mania and also reuptake of these neurotransmitters to synapse will be reduced.

Bipolar disorders: In addition to serotonin , dopamine and norepinephrine neurotransmitter GABA ( gamma amino butyrate) , glutamate and acetylcholine involved in Bipolar disorders.