There are eight subtypes of P2Y receptors (P2Y1, P2Y2, P2Y4
, P2Y6, P2Y11, P2Y12, P2Y13, and P2Y14), which are ubiquitously expressed in body, including the CNS .
Cunha, "Dual presynaptic control by ATP of glutamate release via facilitatory P2X1, P2X2/3, and P2X3 and inhibitory P2Y1, P2Y2, and/or P2Y4
receptors in the rat hippocampus," The Journal of Neuroscience, vol.
The first evidence relating purinergic receptor and fibrosis showed the presence of functional P2Y2, P2Y4
, and P2Y6 receptors in both quiescent and activated HSCs .
ATP and UTP are vasoactive signals able to increase [[[Ca.sup.2+]].sub.i] in the retina, via stimulation of purinergic receptors including P2Y4
Eight subtypes of P2Y have been identified to date--P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12, P2Y13, and P2Y14--with differences in both pharmacology and downstream signalling pathways [3, 4].
UTP is only known to activate P2Y2, P2Y4, and P2Y6 receptors , and, of these, the only receptor responsive to ATP is P2Y2.
Furthermore, both UTP[gamma]S (P2Y2 and P2Y4 selective agonist) and 2-thio-UTP (P2Y2 selective) could induce CCL2 secretion above basal levels but not to the same degree as UTP (full agonist at P2Y2).
There are seven known P2X receptor subtypes (P2X1-7) and eight P2Y receptor subtypes (P2Y1, P2Y2, p2y4
, P2Y6, P2Y11, P2Y12, P2Y13, and P2Y14) .
Burnstock, "Localisation of P2Y1 and P2Y4
receptors in dorsal root, nodose and trigeminal ganglia of the rat," Histochemistry and Cell Biology, vol.
At present, there are eight accepted P2Y receptors: P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12, P2Y13, and P2Y14 [8, 9].
Antibodies against P2Y2, P2Y4, and P2Y6 receptors were from Alomone Labs (Jerusalem, Israel) and other antibodies were from Santa Cruz Biotech (Santa Cruz, CA, USA), from Cell Signaling (Danvers, MA, USA), or from the sources previously described .
The TaqMan probes for mouse EP1, EP2, EP3, EP4, P2Y2, and P2Y4 used in this study were purchased from Applied Biosystems and experiments for validation of amplification efficiency were performed for each TaqMan probe set [28, 29].