Astrocytes（星形胶质细胞） - brain cells named after their characteristic star-shape and previously¹ thought to act only as the 'glue' between neurons（神经原） , have a central role in the regulation of breathing, according to scientists. The finding provides a new dimension for research into fundamental principles of brain organization and function and may be relevant（有关的，中肯的） for understanding causes of devastating² conditions associated with respiratory failure（呼吸衰弱） such as Sudden Infant Death Syndrome³.

The research, funded by the Wellcome Trust and published today in Science Express, was carried out by scientists at UCL and the University of Bristol. They demonstrate that brain astrocytes are able to sense the levels of carbon dioxide in the blood. They then activate⁴ brain neuronal respiratory networks to increase our breathing in accord with（一致） prevailing⁵ metabolism⁶（新陈代谢） and activity.

Astrocytes are a subtype of a group of brain cells known as glia（神经胶质） (which means 'glue' in Greek). Glial cells are the most abundant cells in the human brain – outnumbering neurons by a factor of ten to one. Until very recently, glial cells have been thought to be the less exciting sisters of neurones, merely providing them with structural⁷ and nutritional⁸ support.

Now, astrocytes have been found to have a unique ability to "taste" the composition of arterial（动脉的，干线的） blood entering the brain by sensing increases in arterial levels of carbon dioxide. When activated⁹ they release a chemical messenger called ATP which stimulates¹⁰ brain respiratory centres to increase our breathing in order for extra carbon dioxide to be removed from the blood and exhaled¹¹.

This observation places astrocytes at the centre of a fundamental regulatory reflex which subconsciously¹² continually adjusts our breathing according to ever changing metabolic¹³ and behavioural needs.

Dr Alexander Gourine, a Wellcome Trust Senior Research Fellow in the UCL Department of Neuroscience, Physiology¹⁴ and Pharmacology, who led the study, said: "This research identifies brain astrocytes as previously unrecognized crucial elements of the brain circuits controlling fundamental bodily functions vital for life, such as breathing, and indicates that they are indeed the real stars of the brain.

"This basic science information has to be used rapidly in order to determine whether glial dysfunction（功能紊乱） contributes to serious disorders¹⁵ of central control of breathing underlying¹⁶ Sudden Infant Death Syndrome and/or congenital central hypoventilation（肺换气不足） syndrome (Ondine's curse). If this hypothesis is correct astrocytes may be considered as potential targets for therapy in preventing respiratory（呼吸的） failure".