Researchers from the Baker Research Institute in Melbourne took blood samples from internal jugular veins in more than 100 healthy men in an effort to assess the relation between serotonin concentration and weather conditions and season.

In the past, researchers have concluded that the success of ultraviolet light therapy to stimulate brain neurotransmitter activity and drugs that prevent the reuptake of the neurotransmitter serotonin suggests that serotonin has a role in the development of seasonal affective disorder (SAD).

However, concentrations of serotonin and other neurotransmitters including dopamine and norepinephrine have been shown to be normal in the cerebrospinal fluid of patients with SAD.

In this latest research the experts investigated the subject by looking at serotonin concentrations from blood vessels draining the brain.

They discovered that the turnover of serotonin in winter was lowest and the rate of production of serotonin was directly related to the duration of bright sunlight.

Dr Gavin Lambert comments, “Our observations suggest that the prevailing amount of sunlight affects brain serotonergic activity, and thus underlies mood seasonality and seasonal affective disorder, although we do not know whether patients predisposed to affective disorders are affected by environmental factors in the same way as our healthy volunteers.”

Source: The Lancet

© HMG Worldwide 2002
http://www.health-news.co.uk/