Around 90% of the body's serotonin is made in the gut, not the brain

the gist

Serotonin, also called 5-HT, is a chemical messenger with a huge range of jobs in the body. In the brain and spinal cord it helps regulate mood, appetite, sleep, memory and learning. Most of the body's supply, about 90%, is actually made in the gastrointestinal tract by specialised enterochromaffin cells, where it helps control gut movement. Platelets in the blood pick it up and release it during clotting, which narrows blood vessels and helps stop bleeding. Serotonin is made from the amino acid tryptophan and is broken down mainly in the liver. Antidepressants called SSRIs and SNRIs work by blocking the reabsorption of serotonin at synapses, which raises its level between nerve cells. Serotonin is found across animals, and it also appears in plants, where it can act as a defence by causing pain.

how it works

Enterochromaffin cells in the gut release serotonin, which stimulates nerves that control intestinal movement. In the brain, serotonin is released between neurons and then reabsorbed by transporters, and SSRIs block those transporters so more serotonin stays active between cells.

so what

Because most serotonin is made in the gut, the link between digestion, mood and medication is more than a metaphor. It also explains why drugs that target serotonin can affect bleeding, digestion and sleep as well as emotion.

fun fact

Plants and insect venoms use serotonin as a defensive chemical that causes pain.

Hampi was once one of the world's largest cities, until its Vijayanagara capital was destroyed in 1565

the gist

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.

how it works

The city was built around a fortified core with temples, markets and water structures along the river, supplied by an extensive network of roads and waterworks. When the empire fell, the city was not rebuilt, so its stone monuments were left standing.

so what

Hampi shows how quickly a great city can vanish after a military defeat, and how a ruined capital can remain sacred. Its ruins give historians a view of medieval South Asia that few other sites can match.

fun fact

The name Hampi comes from Pampa, an old name for the Tungabhadra River.

From Wikipedia, the free encyclopedia · text CC BY-SA 4.0

Image: Wikimedia Commons

source: Wikipedia ↗

2 min

politicsshortCNA2:01

False allegations about Singapore’s hand in Indonesia’s markets and a made-up meeting

from CNA

CNA Verify has found close to 400 posts pushing falsehoods tying Singapore to Indonesia’s stock market rout and to a secret meeting that never took place. Together, they drew nearly 12 million views, and some were circulated by accounts that appeared to be working in concert, across multiple social media platforms.

Here’s how the disinformation campaign targeting Singapore was uncovered.

on YouTube: CNA ↗