Aquaporin subtypes in rat cerebral microvessels

We investigated the expression of aquaporin (AQP) subtypes in the rat cerebral microvessels by reverse transcription-polymerase chain reaction, immunoblotting and immunohistochemistry. mRNA for AQP4, but not for AQP1, 2, 3 or 5, was detected in the microvessels. Immunoblot analysis showed that AQP4 protein was detected as a 30 kDa band with higher molecular weight bands. Immunohistochemical staining showed that AQP4 was located on cell surface of the cerebral microvessels. These results suggest that AQP4 in the cerebral microvessels is involved in the regulation of water transport between blood and brain. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.