Читать книгу Trust Your Gut - Gregory Plotnikoff - Страница 23

Western science has increasingly come to consider the gut as much more than just a digestive tract. In the last twenty years, scientists have researched the neuralhormonal complexity of the gut, and more and more are now referring to it as the second brain. The intestinal nervous system (or enteric nervous system) is composed of a cluster of more than 100 million neurons. It has receptors for more than thirty neurotransmitters—the hormones such as epinephrine, serotonin, and dopamine that allow a neuron to send a message to another neuron. In fact, more than 90 percent of the serotonin receptors and more than 50 percent of the dopamine receptors are in the gut.

Of course, the brain in our head is vastly more complex and has a thousand times more neurons than the intestinal brain. However, like the main brain, the intestinal brain receives, organizes, and transmits information. That means that both brains allow rapid and coordinated responses to changes in the environment, and both brains can regulate our internal organs.

The intestinal brain has two main connections to the main brain: a calming route along the vagus nerve and an energizing route along the spinal cord. Both connections operate automatically as part of the autonomic nervous system. When your body/mind is balanced and centered, the calming and energizing parts of your nervous system are likewise balanced. They are complementary. But when these two systems are out of balance, the result is often major intestinal problems like pain, bloating, diarrhea, or constipation.

When your body/mind is balanced and centered, the calming and energizing parts of your nervous system are likewise balanced.

For chronic intestinal problems in which all the life-threatening diseases and maladies have been ruled out, one major cause of dysfunction is that your two brains have somehow gotten their wires crossed. They have become conditioned—just like Pavlov's dog—to react to a threat when no threat exists. That's why it can't be fixed by a pill. The problem is not a disease but rather something closer to a computer virus. It is a system gone awry. The problem is not in your head; it's in your wiring.

Imagine a feedback loop that is out of control—such as a sound system in an auditorium when someone talks into the microphone and you hear a squealing feedback sound. The problem in this loop is that the microphone is oversensitive and picks up not just the normal voice but also the amplified voice over a loudspeaker. Then the microphone sends the amplified voice back through the amplifier and out the speaker again, only louder and more shrill than ever. In a fraction of a second, the shrieking sound gets so loud, it hurts your ears. The speaker has to stop because nobody can hear her anyway, and then you have to turn down the microphone or move the loudspeaker farther away to interrupt the feedback loop.

In the case of an attack of digestive distress, instead of an oversensitive microphone you have a hypersensitized amygdala—a primitive part of the main brain that decides whether a threat exists. It can take a small, harmless sensation and encode it as threatening. This sends a danger signal to the gut, which reacts by tensing up and causing distress. The intestinal brain sends these amplified distress signals back to the amygdala, which totally freaks out and sends more emergency signals back to the gut, so then the gut goes bonkers as well. The feedback loop has gone berserk and keeps accelerating, but instead of a terrible noise in an auditorium, you get awful pain and distress in your gut.