CLONING AND EXPRESSION OF A P-2Y PURINOCEPTOR FROM THE ADULT BOVINE CORPUS-CALLOSUM

We have isolated an ATP receptor clone by screening a bovine corpus ca llosum cDNA library. The clone includes one open reading frame encodin g for a protein of 373 amino acid residues (42 kDa) which belongs to t he G-protein-coupled receptor superfamily. In Xenopus oocytes, this cl one expressed an ATP receptor that triggered an oscillatory current in response to ATP (EC50 approximate to 20 mu M). This current may have resulted from the activation of phospholipase C, the formation of inos itol trisphosphate, and the release of Ca2+, which then opens Cl- chan nels. The order of potency for ATP receptor agonists was 2-MeSATP appr oximate to ATP much greater than alpha,beta-MeATP > adenosine, and UTP was ineffective, a pharmacological profile consistent with that of a P-2y purinoceptor. Northern blot analysis of mRNAs from various bovine brain tissues showed that the gene is expressed in the cerebellum, me dulla, corpus callosum, hippocampus, superior colliculus, frontal cort ex, and retina. In situ RT-PCR showed transcripts of the gene in many glial cells and endothelial cells of the corpus callosum. The cloned r eceptor may play an important role in neuron-glial signaling under nor mal and pathological conditions. (C) 1998 Academic Press.