Pain is the most common symptom reported by patients with rheumatoid arthritis (RA) even after the resolution of chronic joint inflammation. It is believed that RA-associated pain is not solely due to inflammation, but could also be attributed to aberrant modifications to the central nervous system. The P2X4 receptor (P2X4R) is an ATP-activated purinergic receptor that plays a significant role in the transmission of information in the nervous system and pain. The involvement of P2X4R during the pathogenesis of chronic inflammatory pain and neuropathic pain is well-established. The attenuation of this receptor alleviates disease pathogenesis and related symptoms, including hyperalgesia and allodynia. Although some studies have revealed the contribution of P2X4R in promoting joint inflammation in RA, how it implicates pain associated with RA at peripheral and central nervous systems is still lacking. In this review, the possible contributions of P2X4R in the nervous system and how it implicates pain transmission and responses were examined.
Matched MeSH terms: Purinergic P2X Receptor Antagonists/therapeutic use
Mood disorders are a group of psychiatric conditions that represent leading global disease burdens. Increasing evidence from clinical and preclinical studies supports that innate immune system dysfunction plays an important part in the pathophysiology of mood disorders. P2X7 receptor, belonging to the ligand-gated ion channel P2X subfamily of purinergic P2 receptors for extracellular ATP, is highly expressed in immune cells including microglia in the central nervous system (CNS) and has a vital role in mediating innate immune response. The P2X7 receptor is also important in neuron-glia signalling in the CNS. The gene encoding human P2X7 receptor is located in a locus of susceptibility to mood disorders. In this review, we will discuss the recent progress in understanding the role of the P2X7 receptor in the pathogenesis and development of mood disorders and in discovering CNS-penetrable P2X7 antagonists for potential uses in in vivo imaging to monitor brain inflammation and antidepressant therapeutics.
Matched MeSH terms: Purinergic P2X Receptor Antagonists/therapeutic use