Ping-An Zhang1, Qi-Ya Xu1, Lu Xue1, Hang Zheng1, Jun Yan2, Ying Xiao1,3, Guang-Yin Xu1. 1. Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Laboratory of Translational Pain Medicine, Institute of Neuroscience, Soochow University, Suzhou, China. 2. The Second Affiliated Hospital of Soochow University, Suzhou, China. 3. Chengdu Radio and TV University, Chengdu, China.
Abstract
AIMS: Insular cortex (IC) is involved in processing the information of pain. The aim of this study was to investigate roles and mechanisms of P2X7 receptors (P2X7Rs) in IC in development of visceral hypersensitivity of adult rats with neonatal maternal deprivation (NMD). METHODS: Visceral hypersensitivity was quantified by abdominal withdrawal reflex threshold to colorectal distension (CRD). Expression of P2X7Rs was determined by qPCR and Western blot. Synaptic transmission in IC was recorded by patch-clamp recording. RESULTS: The expression of P2X7Rs and glutamatergic neurotransmission in IC was significantly increased in NMD rats when compared with age-matched controls. Application of BzATP (P2X7R agonist) enhanced the frequency of spontaneous excitatory postsynaptic currents (sEPSC) and miniature excitatory postsynaptic currents (mEPSC) in IC slices of control rats. Application of BBG (P2X7R antagonist) suppressed the frequencies of sEPSC and mEPSC in IC slices of NMD rats. Microinjection of BzATP into right IC significantly decreased CRD threshold in control rats while microinjection of BBG or A438079 into right IC greatly increased CRD threshold in NMD rats. CONCLUSION: Data suggested that the enhanced activities of P2X7Rs in IC, likely through a presynaptic mechanism, contributed to visceral hypersensitivity of adult rats with NMD.
AIMS: Insular cortex (IC) is involved in processing the information of pain. The aim of this study was to investigate roles and mechanisms of P2X7 receptors (P2X7Rs) in IC in development of visceral hypersensitivity of adult rats with neonatal maternal deprivation (NMD). METHODS: Visceral hypersensitivity was quantified by abdominal withdrawal reflex threshold to colorectal distension (CRD). Expression of P2X7Rs was determined by qPCR and Western blot. Synaptic transmission in IC was recorded by patch-clamp recording. RESULTS: The expression of P2X7Rs and glutamatergic neurotransmission in IC was significantly increased in NMD rats when compared with age-matched controls. Application of BzATP (P2X7R agonist) enhanced the frequency of spontaneous excitatory postsynaptic currents (sEPSC) and miniature excitatory postsynaptic currents (mEPSC) in IC slices of control rats. Application of BBG (P2X7R antagonist) suppressed the frequencies of sEPSC and mEPSC in IC slices of NMD rats. Microinjection of BzATP into right IC significantly decreased CRD threshold in control rats while microinjection of BBG or A438079 into right IC greatly increased CRD threshold in NMD rats. CONCLUSION: Data suggested that the enhanced activities of P2X7Rs in IC, likely through a presynaptic mechanism, contributed to visceral hypersensitivity of adult rats with NMD.
Authors: M Teresa Miras-Portugal; Álvaro Sebastián-Serrano; Laura de Diego García; Miguel Díaz-Hernández Journal: J Neurosci Date: 2017-07-26 Impact factor: 6.167