Dr. Ron’s Research Review – May 6, 2015

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This week’s research review focuses on chromium and serotonin receptors.

A study found that chromium can modify brain 5-HT function in humans and animals, perhaps by altering the sensitivity of central 5-HT(2A) receptors. (Attenburrow et al., 2002)

The study examined the effects of short-term chromium picolinate supplementation in both rats and humans. Brain 5-HT function was assessed by measuring the corticosterone/cortisol response to the 5-HT precursor, 5-hydroxytryptophan (5-HTP), a response believed to be mediated via indirect activation of 5-HT(2A) receptors.
The human study included eight healthy subjects (seven male, one female) mean age 48 years (range 23–63 years) with no current or past history of psychiatric disorder. Subjects took chromium picolinate 400 μg daily in the morning for 7–9 days.
In rats, chromium increased peripheral and central tryptophan availability and elevated brain 5-HT content. Changes in peripheral tryptophan availability were not seen in humans but in both rats and humans, chromium lowered the cortisol response to challenge with 5-HTP.

The dose of chromium given to the rats (100 mg/kg) was substantially more than that given to the volunteers. A "high dose” is considered 1000mcg chromium/day; and "moderate dose" is 600mcg chromium/day.

Dr. Ron


 

Articles

Chromium treatment decreases the sensitivity of 5-HT2A receptors.
            (Attenburrow et al., 2002) Download
RATIONALE: Recent case series suggest that chromium picolinate in doses of 400 microg daily may have antidepressant properties, perhaps through increasing the peripheral availability of tryptophan for brain serotonin (5-HT) synthesis. OBJECTIVES: To determine the effects of chromium treatment on plasma tryptophan availability and on brain 5-HT function in human and animal models. METHODS: We studied the effects of short-term chromium supplementation on plasma concentrations of tryptophan and other large neutral amino acids. Brain 5-HT function was assessed by measuring the corticosterone/cortisol response to the 5-HT precursor, 5-hydroxytryptophan (5-HTP), a response believed to be mediated via indirect activation of 5-HT(2A) receptors. RESULTS: In rats, chromium increased peripheral and central tryptophan availability and elevated brain 5-HT content. Changes in peripheral tryptophan availability were not seen in humans but in both rats and humans, chromium lowered the cortisol response to challenge with 5-HTP. CONCLUSIONS: Chromium can modify brain 5-HT function in humans and animals, perhaps by altering the sensitivity of central 5-HT(2A) receptors.

 

References

Attenburrow, MJ, et al. (2002), ‘Chromium treatment decreases the sensitivity of 5-HT2A receptors.’, Psychopharmacology (Berl), 159 (4), 432-36. PubMedID: 11823896