Serotonin & Thyroid Interactions

• Thyroid hormone levels are directly related to platelet serotonin levels.
• Low thyroid hormone levels (especially T3) dampens cerebral bioenergetic metabolism which has been directly correlated to Major Depressive Disorder (MDD).
• Thyroid hormones activate 5-TH2A serotonin receptors
• Serotonin is used as a messenger to relaese TSH from the pituitary
• Serotonin is involved with modualting intracellular T3 prodction via type II 5’deiodinase

Dopamine & Thyroid Interaction

• Dopamine levels in the cerebral spinal fluid (CSF) stimulate the paraventricular nucleus
• The paraventricular nucleus stimulates the Hypothalamus-Pituitary-Thyroid Axis
• The HPT Axis modualtes TSH and T3 prodcution

Acetylcholine & Thyroid Interaction

• Thyroid hormone levels affect the activities of AChE in the
  • frontal cortex
  • hipocampus
  • cerebellum
• Hypothyroidism leads to a global loss of cholinergic activity, but with the greatest potential to develop cerebellum degeneration.

GABA & Thyroid Hormone Interactions

• Thyroid hormones
  • modulate GABA Release
  • Activate the conversion of glutamate to GABA
  • Enhances GABA receptor sensitivity
• GABA Issues
  • Low levels and/or low receptor sensitivity leads to anxiety
• GAD-antibodies are present in 5% of Hashimoto patients.