Breast-feeding triggers pulses of feel-good hormone

A Tarahumara child is breastfed by his mother in the hamlet of Rikinapuchi, northern Chihuahua state, Mexico, January 22, 2008.

CHICAGO (Reuters) - When a baby breast-feeds, it triggers a flood of the hormone oxytocin that releases milk from the mammary gland and a feeling of love and trust in the mother that ensures the baby's needs are met.

This reflex has long puzzled researchers because it requires large surges of oxytocin to pull off all of this. Using a special computer model, researchers from China, France, Italy, and the United Kingdom said on Thursday they now understand how it works.

Their study, reported in the journal PLoS Computational Biology, suggests that breast feeding not only taps the normal brain cells involved in secreting oxytocin.

It also recruits dendrites -- whose normal job is to create communication channels between brain cells -- into secreting the hormone.

This increases communication between the neurons and creates a hub of oxytocin production that results in bursts of the hormone released at regular intervals.

"We knew that these pulses arise because, during suckling, oxytocin neurons fire together in dramatic synchronized bursts. But exactly how these bursts arise has been a major problem that has until now eluded explanation," Jianfeng Feng of the University of Warwick in Coventry in the United Kingdom said in a statement.

He said the findings could help explain other similar activities in the brain.

The study can be found here

(Reporting by Julie Steenhuysen; Editing by Eric Walsh)