Cold Exposure

   It is well-established that cold exposure causes transient TSH elevations (91 references).

   As TSH and Free T3 regulate 5-hydroxytryptamine (5-HT) there should be  disturbances in 5-HT observable during cold exposure.

   This has of course been observed numerous times (e.g. Mohamed, 1982; Aly et al, 1985).

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Aly MS, Mohamed MI, Rahman TA, Moustafa S - "Studies of contents of norepinephrine and 5-hydroxytryptamine in brain--I. Normal and cold exposure" Comp Biochem Physiol C 82(1):155-8 (1985)MEDLINE

Mohamed MI, Rahman TA - "Effect of cold exposure on brain
5-hydroxytryptamine and 5-hydroxyindoleacetic acid in some vertebrate species" Comp Biochem Physiol C 73(2):319-22  (1982)MEDLINE

• “1. The changes in 5-HT and 5-HIAA levels were studied in the brain regions of Gerbillus pyramidum, Streptopelia senegalensis aegyptiaca and Agama stellio following exposure to cold. 2. In general, the 5-HT levels increased in the Gerbillus brain parts and decreased in those of Streptopelia. 3. Cold exposure in the Agama brain regions caused a transient decrease in the 5-HT levels of the cerebral hemispheres, midbrain and pons plus medulla after 6 hr and a general increase after 12, 24 and 48 hr. 4. It is concluded that cold exposure may be associated with increased activity of 5-HT ergic neurons and the rate of
  turnover of 5-HT to 5-HIAA.”