It was four and a half centuries later that Galen observed that the pineal structure ... chemical messengers like norepinephrine from the dense pineal sympathetic afferents. In mammals, melatonin ...

Melatonin is actually derived from an amino acid called ... This suppression of nerve cell activity is what causes the feeling of drowsiness. Caffeine has a chemical structure similar to that of ...

“No one was thinking that the melatonin system was affected by these compounds ... “From those, we identified hundreds of thousands of compounds that had readily available chemical structures so that ...

"No one was thinking that the melatonin system was affected by ... of thousands of compounds that had readily available chemical structures so that we could study them," Rajnarayanan explained.