BACKGROUND: The aquaporin (AQP), mainly AQP1, AQP4 and AQP9, are expressed in mammalian brain, while the others are sporadically expressed. There is no evidence concerning the distribution, function and regulation mechanism of AQP in the brain.
OBJECTIVE: To comprehensively analyze the research progress of the distribution, function and regulation mechanism of AQP in maintaining normal physiological function of the brain.
METHODS: An online retrieval of PubMed database and CNKI database between January 1980 and July 2013 was performed for articles on the distribution, function and regulation mechanism of AQP, with the key words of “AQP1, AQP4, AQP9, function, brain, adjusting mechanism” in English and Chinese. A total of 163 papers were screened out and 85 of them met the inclusive criteria.
RESULTS AND CONCLUSION: The existing studies about the expression, function and regulating mechanism of AQP1, AQP4 and AQP9 in the brain can be summarized as the following three aspects: (1) AQP1 is expressed in the choroid plexus and participates in forming cerebrospinal fluid; in other types of cells, gas micromolecules CO2, NO, NH3 and O2 also cross through AQP1. (2) AQP4 is mainly expressed in the astrocytes, ependymal foot process and gelatin membranes, which can help the water in and out of the brain tissue, accelerate glial cell migration and change neural activity. (3) AQP9 is mainly distributed in astrocytes and catecholamine neurons, the main function is involved in energy metabolism in the brain. Therefore, AQP is the key for water transport in the brain. Understanding the distribution, function and regulation mechanism of AQP will play an important role in the treatment of brain diseases. The regulatory mechanism on the expression of AQPs in normal pathology and related disease remains unclear and related molecular signal pathway needs further exploration.