Maternal hormone shuts down baby’s brain cells during birth
It is the instinct of every mother to protect their children as they grow up, shielding them from the dangers of the outside world. Right from birth, life can be a difficult experience. Within a few hours, the child is sent from a safe, warm, constantly-nourished cocoon into a bright, noisy and threatening world. This stressful transition poses a serious threat to the newborn’s vulnerable and still-developing mind. But new research has shown that even in these first vital hours, mothers are already inadvertently protecting their children – by shutting down their brain cells.
In foetuses and new-born mammals, brain activity depends on a vital molecule called gamma-aminobutyric acid, known by the friendlier name of GABA. GABA is a neurotransmitter, a chemical that sends messages between nerve cells, and in young mammals, its message almost always says “Fire.
But Roman Tyzio and colleagues from the Mediterranean University, Marseilles, found that in the brains of baby rats, the message changes just before delivery. For a brief time window, rather than stimulating brain activity, GABA puts a finger to its lips and silences nerve cells instead. During this time, Tyzio saw that the number of cells affected by GABA plummeted to negligible levels.
His group found that this chemical volte face is triggered by the mother, through an all-important, multi-purpose hormone called oxytocin. Oxytocin is another neurotransmitter, and one that is almost synonymous with social relationships. It has been linked to sexual arousal, feelings of trust, love and monogamy. During childbirth, massive amounts of oxytocin are released by the mother and can reach the foetus via the placenta.
Artificially adding oxytocin to the brain tissue of foetal rats caused cells to ignore GABA just as they do before delivery. And giving expectant mothers atosiban, an anti-oxytocin chemical, stopped this from happening. It seems that oxytocin’s long list of abilities now includes temporarily shutting down an infant’s nervous system during birth.
Many mothers might dream of doing the same later on in their child’s life but at this crucial juncture, it protects them from the dangers of oxygen deprivation. A lack of oxygen during birth is the number one cause of death or brain damage in newborns. But because oxytocin silences a baby’s brain cells, it greatly reduces their energy needs and their dependency on oxygen.
Tyzio found that the brain cells of baby rats survived without oxygen for an hour if they were delivered naturally. But if mothers were given atosiban, the brain cells of their babies died within 45 minutes. Other studies in sheep have found that the massive flush of oxytocin during childbirth is crucial if mothers are to form stable emotional ties to their babies. Now, thanks to Tyzio’s team, we know that oxytocin might also be important for the baby’s mental development.
These findings have important implications for human mothers too. The oxytocin spike relies on the baby pressing against the cervix during birth. Those delivered through caesarean sections may miss out on the hormone and all its benefits. Caesarean sections are becoming increasingly popular, mainly as an elective procedure rather than an emergency one. Studies like this could give women who opt for these operations pause for thought.
Reference: R. Tyzio, R. Cossart, I. Khalilov, M. Minlebaev, C. A. Hubner, A. Represa, Y. Ben-Ari, R. Khazipov (2006). Maternal Oxytocin Triggers a Transient Inhibitory Switch in GABA Signaling in the Fetal Brain During Delivery Science, 314 (5806), 1788-1792 DOI: 10.1126/science.1133212
Go Further
Animals
- Octopuses have a lot of secrets. Can you guess 8 of them?
- Animals
- Feature
Octopuses have a lot of secrets. Can you guess 8 of them? - This biologist and her rescue dog help protect bears in the AndesThis biologist and her rescue dog help protect bears in the Andes
- An octopus invited this writer into her tank—and her secret worldAn octopus invited this writer into her tank—and her secret world
- Peace-loving bonobos are more aggressive than we thoughtPeace-loving bonobos are more aggressive than we thought
Environment
- This ancient society tried to stop El Niño—with child sacrificeThis ancient society tried to stop El Niño—with child sacrifice
- U.S. plans to clean its drinking water. What does that mean?U.S. plans to clean its drinking water. What does that mean?
- Food systems: supporting the triangle of food security, Video Story
- Paid Content
Food systems: supporting the triangle of food security - Will we ever solve the mystery of the Mima mounds?Will we ever solve the mystery of the Mima mounds?
- Are synthetic diamonds really better for the planet?Are synthetic diamonds really better for the planet?
- This year's cherry blossom peak bloom was a warning signThis year's cherry blossom peak bloom was a warning sign
History & Culture
- Strange clues in a Maya temple reveal a fiery political dramaStrange clues in a Maya temple reveal a fiery political drama
- How technology is revealing secrets in these ancient scrollsHow technology is revealing secrets in these ancient scrolls
- Pilgrimages aren’t just spiritual anymore. They’re a workout.Pilgrimages aren’t just spiritual anymore. They’re a workout.
- This ancient society tried to stop El Niño—with child sacrificeThis ancient society tried to stop El Niño—with child sacrifice
- This ancient cure was just revived in a lab. Does it work?This ancient cure was just revived in a lab. Does it work?
- See how ancient Indigenous artists left their markSee how ancient Indigenous artists left their mark
Science
- Jupiter’s volcanic moon Io has been erupting for billions of yearsJupiter’s volcanic moon Io has been erupting for billions of years
- This 80-foot-long sea monster was the killer whale of its timeThis 80-foot-long sea monster was the killer whale of its time
- Every 80 years, this star appears in the sky—and it’s almost timeEvery 80 years, this star appears in the sky—and it’s almost time
- How do you create your own ‘Blue Zone’? Here are 6 tipsHow do you create your own ‘Blue Zone’? Here are 6 tips
- Why outdoor adventure is important for women as they ageWhy outdoor adventure is important for women as they age
Travel
- This royal city lies in the shadow of Kuala LumpurThis royal city lies in the shadow of Kuala Lumpur
- This author tells the story of crypto-trading Mongolian nomadsThis author tells the story of crypto-trading Mongolian nomads
- Slow-roasted meats and fluffy dumplings in the Czech capitalSlow-roasted meats and fluffy dumplings in the Czech capital