6.2 - Anti-depressants

What are characteristics of depression?

• Most common mental illness

• Considered a sadness that is incapacitating

What is the neurophysiology of depression and its drug strategy?

• Current theory: Depressions is caused by a defect in the CNS biogenic amine neurotransmitters

• Neurotransmitters

  • Norepinephrine (NE)

  • Dopamine

  • Serotonin

• Drug strategy: Increase or prolong the effects of one or more of the amine neurotransmitters

What are types of antidepressants?

• SSRIs

• SNRIs

• Trycyclics

• MAO inhibitors

• Others

What are common selective serotonin reuptake inhibitors (SSRIs)?

• Fluoxetine

• Paroxetine

• Sertraline

• Citalopram

• Escitalopram

• Fluvoxamine

What are common selective norepinephrine re-uptake inhibitors (SNRIs)

• Desvenlafaxine

• Duloxetine

• Venlafaxine

What are common trycyclics?

• Amitripytine

• Amozapine

• Desipramine

• Imipramine

• Trimipramine

Are tycylics selective?

No they affect all the 3 neurotransmitters associated with depression

What are common manoamine oxidase (MAO) inhibitors?

• Isocarboxazid

• Phenelzine

• Tranylcypromine

What are other anti-depressants?

• Nefazodone, trazodone

  • Block serotonin receptors and reuptake

• Buproprion

  • NE-domapine reuptake inhibitor

• Mitrazapine

  • May block pre-synaptic NE and serotonin receptors

What is the mechanism of anti-depressants?

• Prolong the effects of amine neurotransmitters by either

  • Inhibit reuptake of one or more amine neurotransmitters (SSRI, SNRIs, trycyclics, others)

  • Decreasing neurotransmitter breakdown (MAO inhibitors)

• Overall increase the synaptic connections within the hippocampus where mood and emotions are regulated

Why might increasing or prolonging the effects of neurotransmitters decrease depression?

• Latest theory:

  • Drugs increase the activity of the amine neurotransmitter causing an increased neurotransmitter activity

  • Leads to an increase in brain-derived neurotrophic factor (BDNF)

What does neurotrophic mean?

• Increased growth and development of neuron

  • Makes neuron happy and healthier

What does BDNF do?

Stimulates growth in the hippocampus