Studies have shown a direct link between the gut and the brain

photo Source: NICOLLE R. FULLER/SCIENCE SOURCE
The human gut is lined with more than 100 million nerve cells -- in fact, it's a brain in itself. Indeed, the intestines talk to the brain, releasing hormones into the bloodstream, telling people how hungry it is or how hungry they should be in about 10 minutes or that people shouldn't eat the whole pizza. However, new research suggests that there is a more direct link between the intestine and the brain through a neural circuit that transmits signals within seconds. The findings may lead to new treatments for obesity, eating disorders, and even depression and autism, all of which are associated with dysfunctional guts.
2010, Diego Bohórquez, a neuroscientist at Duke University in the United States, made a startling discovery while looking at an electron microscope. Intestinal endocrine cells scattered in the inner walls of the intestine that promote digestion and suppress hunger hormones have foot-like protrusions similar to those used for communication between neurons. Bohórquez knows that endocrine cells in the intestines can send hormone information to the central nervous system, but he doubts that they can use electrical signals to "talk" to the brain, as neurons do. If so, they will have to send signals through the ecstic nerve that travels through the intestines to the brain.
this, Bohórquez and colleagues injected mice with a fluorescent rabies virus transmitted through synapses and waited for endocrine cells and their "partners" to be lit. As it turns out, these "partners" are the lost neurons. The researchers report the
in a recently published paper.
independent study,
published recently in The New Year, reveals another clue as to how intestinal sensory cells can benefit. The researchers used lasers to stimulate sensory neurons in the intestines of mice. They create a sense of reward that these rodents struggle to repeat. Laser stimulation also increased levels of dopamine, a neurotransmitter that improves mood in the brains of mice.
De Araujo, a neuroscientist at Icahn School of Medicine at Mount Sinai in New York who led the second study, said the two efforts help explain why using currents to stimulate the ecstrain nerve can treat severe depression in humans. These results may also explain why eating makes people feel good. "Even if these neurons are outside the brain, they fit perfectly into the definition of reward neurons," he says, making humans more motivated and more enjoyable. (Source: Zong Hua, China Science Daily)