The new study first revealed that direct, and near instant, communication occurred between the gut and brain. A mouse was administered with a rabies virus that had been engineered with a green fluorescent tag. Tracing the signal of communication as the gut informed the brain of this virus revealed an immediate response in the vagus nerve. In under 100 milliseconds a single signal was seen to travel from the gut to the brainstem. In order to understand this new neural circuit, the team grew enteroendocrine cells in a lab dish alongside vagal nerve neurons. Not only did these two elements rapidly demonstrate communication, but it was discovered that glutamate, a foundational neurotransmitter, modulated the rate of transmission. What this experiment impressively revealed was that enteroendocrine cells don’t solely signal to the brain via hormonal triggers, but also can directly communicate via neural synapses.
A new study has revealed a “fast-acting neural circuit allowing gut cells to communicate with the brain in just seconds,” reports New Atlas. Diego Bohorquez, senior author of the study, says “these findings are going to be the biological basis of a new sense. One that serves as the entry point for how the brain knows when the stomach is full of food and calories.” He says it “brings legitimacy to [the] idea of the ‘gut feeling’ as a sixth sense.” The study has been published in the journal Science. From the report: Remarkable new work from a team of researchers at Duke University has now revealed a previously unknown direct circuit between the gut and the brain that could allow for fast sensory communication that doesn’t relay on laborious hormonal signaling. The research began with a big discovery in 2015 revealing that enteroendocrine cells, the cells in our gut thought to be the primary sensory receptor that communicate with the brain, actually contained nerve endings that seemed like they could directly synaptically communicate with vagal neurons and subsequently, the brain.