Here’s a New York Times article, Job Description Grows for Our Utility Hormone, on the neurotransmitter serotonin.
New findings: it’s manufactured prenatally by the placenta and stimulates the growth of new neural connections in the forebrain, and it plays a role in bone health.
The molecule was first detected in 1948, in blood serum, and it was shown be a vascular toning agent that causes blood vessels to constrict — hence its name, a conjoinment of “serum” and “tone.” Five years later, scientists found serotonin in brain extracts as well, and they soon learned that the recently invented hallucinogenic drug lysergic acid diethylamide worked by tapping into the brain’s serotonin system and that if you took too much LSD you might end up wearing hair garlands and overusing the word “wow.”
For all the intricacy, serotonin in the brain has a basic personality. “It’s a molecule involved in helping people cope with adversity, to not lose it, to keep going and try to sort everything out,” said Philip J. Cowen, a serotonin expert at Oxford University and the Medical Research Council. In the fine phrase of his Manchester University colleague Bill Deakin, “it’s the ‘Don’t panic yet’ neurotransmitter,” said Dr. Cowen.
Given serotonin’s job description, disturbances in the system can contribute to depression, anxiety, panic attacks and mental calcification, an inability to see the world anew — at least in otherwise vulnerable people.
Neuronal serotonin may be better known, but as it happens the vast bulk of the body’s serotonin supply, better than 95 percent, is synthesized outside the brain, mostly by the gut. The two serotonin stocks are kept strictly segregated by the blood-brain barrier, however, and are able to perform on entirely independent pathways.