Overexpression of GRK6 alleviates chronic visceral hypersensitivity through downregulation of P2Y6 receptors in anterior cingulate cortex of rats with prenatal maternal stress

Abstract

Aims: Visceral hypersensitivity is a major clinic symptom in patients with irritable bowel syndrome (IBS). Anterior cingulate cortex (ACC) is involved in processing the information of pain. Both G protein-coupled receptor kinase 6 (GRK6) and P2Y purinoceptor 6 (P2Y6) are associated with neuroinflammation and pathological pain. The aim of this study was to investigate the interaction between GRK6 and P2Y6 in ACC in the development of visceral hypersensitivity of adult offspring rats with prenatal maternal stress (PMS).Methods: Visceral hypersensitivity was quantified by abdominal withdrawal reflex threshold to colorectal distension (CRD). The expression and cellular distribution of GRK6 and P2Y6 were determined by Western blotting, qPCR, and fluorescence immunohistochemistry. Co-immunoprecipitation was used to evaluate the interaction between GRK6 and P2Y6. Results:The mRNA and protein levels of GRK6 were significantly decreased in ACC of PMS rats. The injection of GRK6 overexpression virus significantly attenuated visceral hypersensitivity of PMS rats. P2Y6's mRNA level, protein level, and ratio of membrane protein over total protein expression was markedly increased in PMS rats. P2Y6 antagonist MRS2578 microinjection reversed visceral hypersensitivity of PMS rats.GRK6 overexpression significantly reduced P2Y6's expression in membrane proteins and P2Y6's ratio of membrane protein over total protein expression. Conclusions:These results indicate that decreased GRK6 leads to the accumulation of P2Y6 at neuron membrane in ACC, thereby contributing to visceral hypersensitivity of PMS rats.

Upregulation of KDM6B in the anterior cingulate cortex contributes to neonatal maternal deprivation-induced chronic visceral pain in mice

“…Previous studies have shown that unilateral ACC injection of drugs can relieve chronic visceral pain and cause less harm to animals. 29 , 60 This was confirmed by our results.…”

“…In multiple animal models of chronic visceral pain, the ACC show dramatically activation. 25 – 29 The ACC contributes to the development of chronic visceral pain by regulating the function of diverse molecules and neural circuits. 14 , 30 – 34 …”

A paraventricular hypothalamic nucleus input to ventral of lateral septal nucleus controls chronic visceral pain

“…At each injection site, the needle was left in place for 10 to 15 minutes after the completion of the injection to allow the viral spread, and subsequently, it was slowly withdrawn. Because unilateral injection of the virus can change pain behavior fully 35 , 37 and bilateral injections might cause more damage to the brain tissue than unilateral injection, the unilateral injection (right hemisphere) was performed in this study.…”