Purinergic Signalling (2012) 8 (Suppl 1):S61–S79 DOI 10.1007/s11302-011-9278-z ORIGINAL ARTICLE Using antibodies against P2Y and P2X receptors in purinergic signaling research Dovrat Brass & Melanie R. Grably & Noemi Bronstein-Sitton & Ofra Gohar & Alon Meir Received: 27 September 2011 / Accepted: 13 October 2011 / Published online: 16 November 2011 # The Author(s) 2011. This article is published with open access at Springerlink.com Abstract The broad expression pattern of the G protein- coupled P2Y receptors has demonstrated that these receptors are fundamental determinants in many physiological responses, including neuromodulation, vasodilation, inflam- mation, and cell migration. P2Y receptors couple either Gq or Gi upon activation, thereby activating different signaling pathways. Ionotropic ATP (P2X) receptors bind extracellular nucleotides, a signal which is transduced within the P2X protein complex into a cation channel opening, which usually leads to intracellular calcium concentration elevation. As such, this family of proteins initiates or shapes several cellular processes including synaptic transmission, gene expression, proliferation, migration, and apoptosis. The ever-growing range of applications for antibodies in the last 30 years attests to their major role in medicine and biological research. Antibodies have been used as therapeutic tools in cancer and inflammatory diseases, as diagnostic reagents (flow cytometry, ELISA, and immunohistochemistry, to name a few applications), and in widespread use in Dovrat Brass, Melanie R. Grably, Noemi Bronstein-Sitton, Ofra Gohar, and Alon Meir contributed equally to this manuscript. D. Brass : M. R. Grably (*) : N. Bronstein-Sitton : O. Gohar : A. Meir Alomone Labs Ltd., P.O. Box 4287, Jerusalem 91042, Israel e-mail: melanie@alomone.com D. Brass e-mail: dovratbr@alomone.com N. Bronstein-Sitton e-mail: emi@alomone.com O. Gohar e-mail: ogohar@alomone.com A. Meir e-mail: alon@alomone.com biological research, including Western blot, immunoprecip- itation, and ELISPOT. In this article, we will showcase several of the advances that scientists around the world have achieved using the line of antibodies developed at Alomone Labs for P2Y and P2X receptors. Keywords Purinergic signaling . Purinoceptors . P2Y receptors . Antibodies . G protein-coupled receptors . P2X receptors . Ion channels P2Y receptors P2Y receptors can be divided into two main subgroups: the P2Y1 subfamily which comprises P2Y1, P2Y2, P2Y4, P2Y6, and P2Y11 receptor subtypes. They all couple to Gq, thereby activating phospholipase C. They are all activated by various nucleotides, although P2Y11 is the sole receptor specifically activated by ATP [1]. Various cellular functions are attributed to these receptors in various tissues and organs such as the brain, autonomic nervous system, epithelia of the airway, gastrointestinal (GI) tract, kidney, eye, vascular tissue, and the immune and inflam- matory cells [1]. The second group, the P2Y12 subfamily, includes the P2Y12, P2Y13, and P2Y14 receptors, which share little homology with members of the P2Y1 subfamily and are generally known to couple Gi. P2Y12 and P2Y13 are mostly activated by ADP, while P2Y14 is activated by UDP-glucose and other nucleotide sugars. Signaling via the latter is relatively in its early stage of understanding [1]. The P2Y12 receptor has an important role in platelets, is highly expressed in the brain, and mediates microglia migration in response to inflammation. P2Y13 is also expressed in the brain as well as in the spleen. P2Y14 is highly expressed in the brain, placenta, neutrophils,