Arcuate Src activation-induced phosphorylation of NR2B NMDA subunit contributes to inflammatory pain in rats

Abstract

The tyrosine kinases of Src family play an important role in the central sensitization following peripheral inflammation. However, whether the Src family in the arcuate nucleus (ARC) of mediobasal hypothalamus is involved in central sensitization remains unknown. The aim of this study was to investigate the role and mechanisms of tyrosine kinases of Src family in N-methyl-d-aspartate (NMDA) receptor activity in the ARC following peripheral inflammation. Peripheral inflammation was induced by unilateral injection of complete Freund's adjuvant (CFA) into rat hindpaw. The neuronal activities of the ARC were recorded using electrophysiological field recording from the in vitro mediobasal hypothalamic slices from control and CFA rats. Expression of total and phosphorylated Src and NR2B subunit protein was analyzed by Western blot and immuoprecipitation. Our results showed that CFA injection resulted in an increase in mechanical and thermal sensitivity, which was partially blocked by neonatal monosodium glutamate treatment. CFA injection also enhanced spontaneous firings of ARC neurons, which were reversed by the NMDA receptor NR2B subunit specific antagonist Ro25-6981 and by PP2, an Src family tyrosine kinase inhibitor. In addition, peripheral inflammation enhanced Src phosphorylation and NMDA receptor NR2B subunit phosphorylation without alteration of total NR2B subunit expression in the ARC. Peripheral inflammation also increased the association of NR2B protein with p-Src protein in the ARC. Administration of PP2 blocked the upregulation of NR2B phosphorylation induced by CFA injection. Taken together, our present results suggest that the arcuate Src activation-induced tyrosine phosphorylation of NR2B NMDA subunit may contribute to inflammatory pain.

The Src family kinase inhibitor dasatinib delays pain-related behaviour and conserves bone in a rat model of cancer-induced bone pain

“…The NR2B subunit is predominantly expressed in the superficial dorsal horn and has been identified as the key Src-mediated-tyrosine-phosphorylated subunit in the NMDA receptor complex 33 . It has been proposed to be involved in development of spinal plasticity and hyperalgesia after inflammatory and neuropathic pain 30, 48 as well as cancer-induced bone pain 49–51 . Liu et al .…”

“…Phosphorylation of Src induce phosphorylation of the NMDA receptors which up-regulates the receptor activity and increases its channel open time and its opening probability 27–29 . It has been shown that activation of Src contributes to inflammatory pain through phosphorylation of the NR2B in rats 30, 31 . Furthermore, Liu and colleagues reported in 2008 that blocking the interaction between Src and the NMDA receptor complex with a peptide mimicking the amino acid sequence of the unique domain of Src ameliorates inflammatory and neuropathic pain 32, 33 and recently Felice et al .…”

Src Family Kinase Inhibitors and their Role in the Treatment of Traumatic Brain Injuries

“…SFKs regulate NR2 subunits of NMDARs through tyrosine phosphorylation, which has been found by physiological and pharmacological studies to be imperative for inducing LTP within the hippocampus [34,[44][45][46]. For example, applying SFK-activating peptide (pYEEI) to cultured hippocampal slices causes an increase in NMDAR current, while Fyn-deficient mice undergoing the MWM task, a behavioral task that is considered to be hippocampal dependent, were impaired.…”

Tyrosine phosphorylation of the NR2B subunit of the NMDA receptor in the spinal cord contributes to chronic visceral pain in rats

“…However, this type of nonspecific subunit receptor antagonist may induce severe side effects such as learning and memory impairment, sensory or motility disorders, and hyperactivity (Jevtovic-Todorovic et al, 1998). The good news is that subtype-specific drugs which selectively target NR2B subunit-containing receptors may show greater promise as analgesics for neuropathic pain due to their reduced side effects (Boyce et al, 1999;Qu et al, 2009;Xu et al, 2012). The NR2B subunit selective antagonist, Ro 25-6981, is more selective than MK-801 (Fischer et al, 1997).…”

“…The subtype-specific drugs may show greater promise as analgesics for chronic pain due to their reduced side effects (Boyce et al, 1999;Qu et al, 2009;Xu et al, 2012). Particularly, spinal cord NR2B subunit is responsible for the central sensitization (Pedersen and Gjerstad, 2008).…”