Irritable bowel syndrome(IBS)is a common functional bowel disorder characterized by abdominal pain and visceral hypersensitivity.Reducing visceral hypersensitivity is the key to effectively relieving abdominal pain in...Irritable bowel syndrome(IBS)is a common functional bowel disorder characterized by abdominal pain and visceral hypersensitivity.Reducing visceral hypersensitivity is the key to effectively relieving abdominal pain in IBS.Increasing evidence has confirmed that the thalamic nucleus reuniens(Re)and 5-hydroxytryptamine(5-HT)neurotransmitter system play an important role in the development of colorectal visceral pain,whereas the exact mechanisms remain largely unclear.In this study,we found that high expression of the 5-HT2B receptors in the Re glutamatergic neurons promoted colorectal visceral pain.Specifically,we found that neonatal maternal deprivation(NMD)mice exhibited visceral hyperalgesia and enhanced spontaneous synaptic transmission in the Re brain region.Colorectal distension(CRD)stimulation induced a large amount of c-Fos expression in the Re brain region of NMD mice,predominantly in glutamatergic neurons.Furthermore,optogenetic manipulation of glutamatergic neuronal activity in the Re altered colorectal visceral pain responses in CON and NMD mice.In addition,we demonstrated that 5-HT2B receptor expression on the Re glutamatergic neurons was upregulated and ultimately promoted colorectal visceral pain in NMD mice.These findings suggest a critical role of the 5HT2B receptors on the Re glutamatergic neurons in the regulation of colorectal visceral pain.展开更多
Chronic loss of sleep damages health and disturbs the quality of life.Long-lasting sleep deprivation(SD)as well as sleep abnormalities are substantial risk factors for major depressive disorder,although the underlying...Chronic loss of sleep damages health and disturbs the quality of life.Long-lasting sleep deprivation(SD)as well as sleep abnormalities are substantial risk factors for major depressive disorder,although the underlying mechanisms are not clear.Here,we showed that chronic SD in mice promotes a gradual elevation of extracellular ATP,which activates astroglial P2X7 receptors(P2X7Rs).Activated P2X7Rs,in turn,selectively down-regulated the expression of 5-HT2B receptors(5-HT2BRs)in astrocytes.Stimulation of P2X7Rs induced by SD selectively suppressed the phosphorylation of AKT and FoxO3 a in astrocytes,but not in neurons.The overexpression of FoxO3a in astrocytes inhibited the expression of 5-HT2BRs.Down-regulation of 5-HT2BsRs instigated by SD suppressed the activation of STAT3 and relieved the inhibition of Ca2+-dependent phospholipase A2.This latter cascade promoted the release of arachidonic acid and prostaglandin E2.The depression-like behaviors induced by SD were alleviated in P2X7R-KO mice.Our study reveals the mechanism underlying chronic SD-induced depression-like behaviors and suggests 5-HT2BRs as a key target for exploring therapeutic strategies aimed at the depression evoked by sleep disorders.展开更多
基金supported by grants from the National Natural Science Foundation of China (81920108016 and 32230041)the Priority Academic Program Development of Jiangsu Higher Education Institutions of Chinathe Chinese Red Cross Foundation National Brain Nutrition Research Fund.
文摘Irritable bowel syndrome(IBS)is a common functional bowel disorder characterized by abdominal pain and visceral hypersensitivity.Reducing visceral hypersensitivity is the key to effectively relieving abdominal pain in IBS.Increasing evidence has confirmed that the thalamic nucleus reuniens(Re)and 5-hydroxytryptamine(5-HT)neurotransmitter system play an important role in the development of colorectal visceral pain,whereas the exact mechanisms remain largely unclear.In this study,we found that high expression of the 5-HT2B receptors in the Re glutamatergic neurons promoted colorectal visceral pain.Specifically,we found that neonatal maternal deprivation(NMD)mice exhibited visceral hyperalgesia and enhanced spontaneous synaptic transmission in the Re brain region.Colorectal distension(CRD)stimulation induced a large amount of c-Fos expression in the Re brain region of NMD mice,predominantly in glutamatergic neurons.Furthermore,optogenetic manipulation of glutamatergic neuronal activity in the Re altered colorectal visceral pain responses in CON and NMD mice.In addition,we demonstrated that 5-HT2B receptor expression on the Re glutamatergic neurons was upregulated and ultimately promoted colorectal visceral pain in NMD mice.These findings suggest a critical role of the 5HT2B receptors on the Re glutamatergic neurons in the regulation of colorectal visceral pain.
基金the National Natural Science Foundation of China(81871852,81200935,81671862,and 81871529)Liaoning Revitalization Talents Program(XLYC1807137)+1 种基金the Scientific Research Foundation for Overseas Scholars of the Education Ministry of China(20151098)the Natural Science Foundation of Liaoning Province,China(20170541030)。
文摘Chronic loss of sleep damages health and disturbs the quality of life.Long-lasting sleep deprivation(SD)as well as sleep abnormalities are substantial risk factors for major depressive disorder,although the underlying mechanisms are not clear.Here,we showed that chronic SD in mice promotes a gradual elevation of extracellular ATP,which activates astroglial P2X7 receptors(P2X7Rs).Activated P2X7Rs,in turn,selectively down-regulated the expression of 5-HT2B receptors(5-HT2BRs)in astrocytes.Stimulation of P2X7Rs induced by SD selectively suppressed the phosphorylation of AKT and FoxO3 a in astrocytes,but not in neurons.The overexpression of FoxO3a in astrocytes inhibited the expression of 5-HT2BRs.Down-regulation of 5-HT2BsRs instigated by SD suppressed the activation of STAT3 and relieved the inhibition of Ca2+-dependent phospholipase A2.This latter cascade promoted the release of arachidonic acid and prostaglandin E2.The depression-like behaviors induced by SD were alleviated in P2X7R-KO mice.Our study reveals the mechanism underlying chronic SD-induced depression-like behaviors and suggests 5-HT2BRs as a key target for exploring therapeutic strategies aimed at the depression evoked by sleep disorders.
