Posted by saw on October 14, 2004, at 4:13:59
Interesting article
Sabrina"The Second Brain
“Have you ever wondered why people get butterflies in the stomach before going on stage? Or why an impending job interview can cause an attack of intestinal cramps? And why do antidepressants targeted for the brain cause nausea or abdominal upset in millions of people who take such drugs? The reason for these common experiences is because each of us literally has two brains—the familiar one encased in our skulls and a lesser-known but vitally important one found in the human gut. Like Siamese twins, the two brains are interconnected; when one gets upset, the other does, too.” So writes science journalist Sandra Blakeslee for the New York Times. Indeed, the human digestive tract contains over one million nerve cells, about the same number found in the spinal cord. There are actually more nerve cells in the overall digestive system than in the peripheral nervous system. Furthermore, major neurotransmitters found in the brain—including serotonin, dopamine, glutamate, norepinephrine and nitric oxide—occur plentifully in the gut as well. Enkephalins—described as the body’s natural opiates—also occur in the intestinal tract, as do benzodiazepines, psychoactive chemicals similar to mood-controlling drugs like Valium and Xanax.
Jordan Rubin describes the “brain-gut” connection very well in his book The Maker’s Diet:
“ Early in our embryogenesis, a collection of tissue called the ‘neural crest’ appears and divides during fetal development. One part turns into the central nervous system, and the other migrates to become the enteric nervous system. Both ‘thinking machines’ form simultaneously and independently of one another until a later stage of development.
“Then the two nervous systems link through a neural cable called the “vagus nerve,” the longest of all cranial nerves. . . The vagus nerve “wanders” from the brain stem through the organs in the neck and thorax and finally terminates in the abdomen. This is your vital brain-gut connection.”
Serotonin in the gut is thought to initiate peristalsis, the rhythmic movement of food through the digestive tract. Drugs like Prozac actually divert serotonin from the intestinal tract to the brain, leading to digestive problems including constipation in many patients.
The gut produces the same pain-alleviating chemicals as those in antianxiety drugs. Says Rubin, “If you overeat because you feel anxious, your body may be trying to use the extra food to produce more benzodiazepines. We are not sure whether the gut synthesizes benzodiazepine from chemicals in our foods, from bacterial actions or from both. We do know that extreme pain appears to put the gut into overdrive in order to send benzodiazepine directly to the brain for immediate pain management.”
poster:saw
thread:402887
URL: http://www.dr-bob.org/babble/20041012/msgs/402887.html