Vitamin D and Pain: Vitamin D and Its Role in the Aetiology and Maintenance of Chronic Pain States and Associated Comorbidities

Box 3

Potential interfaces of Vitamin D, pain, sleep, and depression.

(i) Anatomical colocalization and functional interaction of central serotonergic, noradrenergic, and dopaminergic systems.

(ii) Inhibition or potentiation of other neurotransmitters such as substance P, acetylcholine, glutamate,

  adenosine, GABA, and monoamine.

(iii) Mediation of immune cells such as astrocytes, macrophages, and phagocytic (monocytes, neutrophils) cells.

(iv) Immune system modulation of proinflammatory mediators such as cytokines and chemokines, especially

  IL-1beta and TNF-, and including NFB, IL-2, IL-6, and CRP.

(v) Immune system modulation of T cell responses inhibiting the production of IL-2, IL-17, and IL-21, and by

  stimulating IL-4 and IL-10 production.

(vi) Immune system modulation via synthesis and/or release of growth hormone releasing hormone,

  prostaglandin-D₂, adenosine, and NO.

(vii) Influence on the hypothalamus–pituitary–adrenal axis and corticosteroid levels