Regional and cellular distribution of the P2Y(1) purinergic receptor in the human brain: Striking neuronal localisation

The biological actions of extracellular nucleotides are exerted via two fam ilies of P2 receptors, P2X and P2Y. The metabotropic P2Y receptors comprise at least 7 distinct subtypes, which have been cloned from a number of spec ies. However, none of the P2Y receptor proteins have been visualised yet in human brain. In the present study, the regional and cellular distribution of the P2Y(1) receptor was investigated in the human brain by using immunoh istochemistry. Polyclonal antibodies were raised against a synthetic peptid e from the C-terminus of the P2Y(1) protein. Immunoblot analysis demonstrat ed that P2Y(1) antiserum specifically recognised a 63-kDa band in human and rat brain membranes. Similarly, the antiserum specifically detected the hu man P2Y(1) receptor in transfected 1321N1 cells. Immunohistochemical analys is on perfusion-fixed human brain tissue showed a widespread distribution f or this receptor throughout the brain. At the cellular level, the P2Y(1) re ceptor was strikingly localised to neuronal structures of the cerebral cort ex, cerebellar cortex, hippocampus, caudate nucleus, putamen, globus pallid us, subthalamic nucleus, red nucleus, and midbrain. Expression of the P2Y(1 ) receptor was not detected in other non-neuronal cell types. These results provide the first characterisation of the cellular distribution of a P2Y r eceptor in the human brain. The widespread and abundant distribution of the P2Y(1) receptor suggests its involvement in a number of important function s within the human brain. The neuronal localisation of this receptor points towards a possible role in neurotransmission, and also highlights a major role for extracellular nucleotides as signaling molecules within the brain. (C) 2000 Wiley-Liss, Inc.