Role of Spinal P2Y₆ and P2Y₁₁ Receptors in Neuropathic Pain in Rats: Possible Involvement of Glial Cells

Abstract

BackgroundThe participation of spinal P2X receptors in neuropathic pain is well recognized. However, the role of P2Y receptors has been less studied. The purpose of this study was to investigate the contribution of spinal P2Y6,11 receptors following peripheral nerve damage induced by spinal nerve ligation. In addition, we determined the expression of P2Y6,11 receptors in the dorsal spinal cord in presence of the selective P2Y6,11 receptors antagonists. Furthermore, we evaluated the participation of spinal microglia and astrocytes in the pronociceptive role of P2Y6,11 receptors.ResultsSpinal administration of the selective P2Y6 (MRS2578, 10–100 μM) and P2Y11 (NF340, 0.3–30 μM) receptor antagonists reduced tactile allodynia in spinal nerve ligated rats. Nerve injury increased the expression of P2Y6,11 receptors at 7, 14 and 21 days after injury. Furthermore, intrathecal administration of MRS2578 (100 μM/day) and NF340 (30 μM/day) for 3 days significantly reduced spinal nerve injury-induced increase in P2Y6,11 receptors expression, respectively. Spinal treatment (on day 14 after injury) with minocycline (100 μg/day) or fluorocitrate (1 nmol/day) for 7 days reduced tactile allodynia and spinal nerve injury-induced up-regulation in Iba-1 and GFAP, respectively. In addition, minocycline reduced nerve injury-induced up-regulation in P2Y6,11 receptors whereas that fluorocitrate diminished P2Y11, but not P2Y6, receptors up-regulation. Intrathecal treatment (on day 21 after injury) with the selective P2Y6 (PSB0474, 3–30 μM) and P2Y11 (NF546, 1–10 μM) receptor agonists produced remarkable tactile allodynia in nerve ligated rats previously treated with minocycline or fluorocitrate for 7 days.ConclusionsOur data suggest that spinal P2Y6 is present in spinal microglia while P2Y11 receptors are present in both spinal microglia and astrocytes, and both receptors are up-regulated in rats subjected to spinal nerve injury. In addition, our data suggest that the spinal P2Y6 and P2Y11 receptors participate in the maintenance of neuropathic pain.

Purinergic signaling triggers endfoot high-amplitude Ca2+ signals and causes inversion of neurovascular coupling after subarachnoid hemorrhage

“…This inhibitor cocktail contained MRS 2179 (30 mM, P2Y 1 antagonist), AR-C 118925XX (10 mM, P2Y 2 antagonist), MRS 2578 (30 mM, P2Y 6 antagonist), and NF 340 (30 mM, P2Y 11 antagonist). [30][31][32] This combination of P2Y inhibitors blocked eHACSs, but did not alter ''control-like'' events or the overall frequency of spontaneous Ca 2þ signals (Figure 3(d) to (f), n ¼ 13 endfeet from 6 brain slices, N ¼ 5). Interestingly, treatment of SAH brain slices with the phospholipase C inhibitor, U73122 (30 mM, 30 min) abolished both SAH-induced eHACSs and all ''control-like'' events (0.026 AE 0.007 Hz to 0 Hz, n ¼ 5 endfeet from 3 brain slices, N ¼ 3).…”

A critical look at the function of the P2Y11 receptor

“…Other antibodies have also been used to examine the existence of the murine P2Y 11 . The P2Y 11 antibody #AB9590 targeting the human P2Y 11 C-terminus detects a large, 75-kDa band on western blot, which is believed to be P2Y 11 on the basis of the results of experiments using rat tissue [41,42], and it has been claimed that another antibody with an unknown epitope confirms P2Y 11 receptor expression in rat neutrophils with a 40-kDa signal [43].…”

“…It is also worth noting that NF157, NF340, and NF546 have all been used to study the murine BP2Y 11 -like receptort hat shows many of the same properties as seen in humans [14,[41][42][43][82][83][84]. Assuming that no P2Y 11 receptor exists in murines, these compounds must have other mechanisms by which they interfere with cell signalling.…”

Celecoxib alleviates oxaliplatin-induced hyperalgesia through inhibition of spinal ERK1/2 signaling

“…Characteristic features of neuropathic pain are hyperalgesia, allodynia, and spontaneous pain. Numerous pieces of evidence have shown that upregulation of spinal pain mediators and related receptors contributes to neuropathic pain 21 , 22 .…”