“rheum”, which is the name for discharge from your nose, mouth or eyes during sleep. More specifically, eye rheum is known as “gound”. Gound is made up of a mixture of dust, blood cells, skin cells, etc. mixed with mucus secreted by the conjunctiva, as well as an oily substance from the meibomian glands. The meibomian glands are a type of sebaceous gland that line the rim of the eyelids with about fifty on the top and twenty five on the bottom of each eye. They secrete an oily substance called meibum that performs a variety of functions including: helps seal your eyes in an air tight fashion when they are closed; prevents tears from spilling onto your cheeks; and helps keep tears that coat your eyes from evaporating. It is this oily substance that is one of the primary components in gound, mixed with mucin from the conjunctiva and various foreign particles in your eye. Normally, when you are awake, the gound is naturally washed away via tears and the blinking motion. However, as you sleep, you obviously don’t blink so the meibomian secretions and other components of the gound tend to gather in the corners of your eyes, as well as along your eye lines and dries out, creating hard yellow-ish “eye boogers”.
Serotonin, Bones, Stress, Osteoporosis - cool little connection
gut serotonin can directly control bone formation. It is released into the blood, and the more serotonin that reaches bone, the more bone is lost. Conversely, the less serotonin, the denser and stronger bones become. Dr. Karsenty was even able to prevent menopause-induced osteoporosis in mice by slowing serotonin production.
Ninety-five percent of the body’s serotonin is made by the gut, but gut serotonin cannot enter the brain because it is barred by a membrane, the so-called blood-brain barrier.
a gene in the gut, Lrp5, controlled serotonin synthesis. Manipulating this gene caused changes in bone formation. Thus, Dr. Karsenty concludes, “The findings demonstrate without a doubt that serotonin from the gut is acting as a hormone to regulate bone mass.”
Working primarily with mice, they set out by introducing genetic mutations that reduced production of the Lrp5 gene in the gut. This caused higher than normal levels of gut serotonin and also low bone mass. Next they introduced a mutation that increased Lrp5 activity, which resulted in lower levels of gut serotonin and denser bones.
gut-produced serotonin does not cross the blood-brain barrier (as SSRI class drugs do), and so is not directly related to that manufactured by the brain. But Dr. Rubman reminds us that this does not mean it doesn’t play a role in stress. For example, think about that queasy feeling you get in your stomach before making a speech or opening your credit card bill. Both kinds of serotonin — that produced in the gut as well as that produced in the brain — help soothe this type of stress by contributing to our ability to maintain equanimity in the face of challenges.
So the idea is that serotonin is required to deal with daily or continuous stresses, and just as the stress can be damaging, the large amounts of serotonin needed to deal with that stress may have some undesirable effects as well.