Oxytocin has been found to modulate and improve pain in humans,but the mechanisms underlying these antinociceptive properties,especially in visceral hypersensitivity,are still unclear.Irritable bowel syndrome(IBS)mode...Oxytocin has been found to modulate and improve pain in humans,but the mechanisms underlying these antinociceptive properties,especially in visceral hypersensitivity,are still unclear.Irritable bowel syndrome(IBS)models were established by colorectal distention in newborn rats aged 8 to 14 days,and visceral hypersensitivity was assessed using electromyogram(EMG).Oxytocin or saclofen was administered intrathecally to evaluate visceral hypersensitivity in the rats.The protein expressions of oxytocin receptor(OTR),γ-aminobutyric acid type B1 receptor(GABAB1),and transient receptor potential vanilloid 1(TRPV1)in the lumbosacral spinal cord regions were measured.IBS rats exhibited a unique spinal cord molecular signature comprising decreased OTR/GABAB1 and increased TRPV1 expression.Intrathecal oxytocin treatment not only normalized these molecular alterations(increasing GABAB1 while decreasing TRPV1)but also ameliorated visceral pain behaviors.Crucially,this therapeutic effect was fully reversed by GABAB1 inhibition,establishing the necessity of intact GABAergic signaling for oxytocin-mediated analgesia.Collectively,these findings indicate that oxytocin relieves visceral hypersensitivity through the regulation of GABAB1 and TRPV1 in the spinal cord of IBS rats.展开更多
Background:Baicalin(BC)and geniposide(GD)are effective components of natural remedies,and studies have shown that they protect against cerebral ischemic stroke(CIS).Transient receptor potential vanilloid 4(TRPV4)is a ...Background:Baicalin(BC)and geniposide(GD)are effective components of natural remedies,and studies have shown that they protect against cerebral ischemic stroke(CIS).Transient receptor potential vanilloid 4(TRPV4)is a calcium-permeable channel that plays important roles in vascular function and vasodilation.However,no studies are available on the effect of BC/GD on the TRPV4 channel and rat cerebral basilar artery(CBA).This study examined the effect of the combination of BC/GD(7:3)on cerebral vascular function after CIS.Methods:We used western blotting to determine TRPV4 protein levels and live cell fluorescence Ca 2+imaging and patch clamp to determine how BC/GD activates TRPV4 channels.Isolated vessel experiments were used to observe the dilatory effects of BC/GD on CBA under different conditions.Laser Doppler imaging was used to measure cerebral blood flow in rats.Triphenyl tetrazolium chloride and Nissl stainings were used to determine the infarct area in the rat brain and neuronal damage,respectively.Results:BC/GD significantly boosted TRPV4 protein levels in vascular smooth muscle cells(VSMCs)during oxygen-glucose deprivation and increased[Ca 2+]i in TRPV4-HEK 293 cells and VSMCs.This effect was not observed in vector-HEK 293 cells.In patch clamp experiments,BC/GD increased Ca 2+currents in TRPV4-HEK 293 cells,whereas no significant changes were observed in vector-HEK 293 cells.BC/GD dilated CBA contractions induced by U46619 and KCl,with a concentration-dependent increase of the dilatory effect.In the middle cerebral artery occlusion model,cerebral blood flow in the ischemic side significantly decreased,whereas BC/GD intervention significantly increased cerebral blood perfusion in the ischemic side,reduced the infarct area,and improved neurological function scores and neuronal damage.Conclusion:BC/GD activates the TRPV4 channel,leading to Ca ^(2+) influx,which in turn activates the intermediate conductance calcium-activated potassium channels channel to regulate vasodilation in vascular smooth muscle.展开更多
基金supported by the National Natural Science Foundation of China(No.82471229)Science and Technology Collaborative Innovation Fund of Fujian Province(No.2021Y9172)the Natural Science Foundation of Fujian Province,China(No.2023J01169)。
文摘Oxytocin has been found to modulate and improve pain in humans,but the mechanisms underlying these antinociceptive properties,especially in visceral hypersensitivity,are still unclear.Irritable bowel syndrome(IBS)models were established by colorectal distention in newborn rats aged 8 to 14 days,and visceral hypersensitivity was assessed using electromyogram(EMG).Oxytocin or saclofen was administered intrathecally to evaluate visceral hypersensitivity in the rats.The protein expressions of oxytocin receptor(OTR),γ-aminobutyric acid type B1 receptor(GABAB1),and transient receptor potential vanilloid 1(TRPV1)in the lumbosacral spinal cord regions were measured.IBS rats exhibited a unique spinal cord molecular signature comprising decreased OTR/GABAB1 and increased TRPV1 expression.Intrathecal oxytocin treatment not only normalized these molecular alterations(increasing GABAB1 while decreasing TRPV1)but also ameliorated visceral pain behaviors.Crucially,this therapeutic effect was fully reversed by GABAB1 inhibition,establishing the necessity of intact GABAergic signaling for oxytocin-mediated analgesia.Collectively,these findings indicate that oxytocin relieves visceral hypersensitivity through the regulation of GABAB1 and TRPV1 in the spinal cord of IBS rats.
基金supported by the Chinese Medicine"Dual Chain Integration"Young and Middle-aged Scientific Research and Innovation Teams(No.2022-SLRH-YQ-006)the Key R&D Programme Projects of Xianyang Municipality(No.L2023-ZDYF-SF-014)+1 种基金the Shaanxi University of Traditional Chinese Medicine Science,Education and Research Collaborative Educational Achievement Transformation Project(No.2024KC03)the open research topic from the Key Laboratory of Neurological Diseases in Traditional Chinese Medicine,Shaanxi Province(No.KF202315).
文摘Background:Baicalin(BC)and geniposide(GD)are effective components of natural remedies,and studies have shown that they protect against cerebral ischemic stroke(CIS).Transient receptor potential vanilloid 4(TRPV4)is a calcium-permeable channel that plays important roles in vascular function and vasodilation.However,no studies are available on the effect of BC/GD on the TRPV4 channel and rat cerebral basilar artery(CBA).This study examined the effect of the combination of BC/GD(7:3)on cerebral vascular function after CIS.Methods:We used western blotting to determine TRPV4 protein levels and live cell fluorescence Ca 2+imaging and patch clamp to determine how BC/GD activates TRPV4 channels.Isolated vessel experiments were used to observe the dilatory effects of BC/GD on CBA under different conditions.Laser Doppler imaging was used to measure cerebral blood flow in rats.Triphenyl tetrazolium chloride and Nissl stainings were used to determine the infarct area in the rat brain and neuronal damage,respectively.Results:BC/GD significantly boosted TRPV4 protein levels in vascular smooth muscle cells(VSMCs)during oxygen-glucose deprivation and increased[Ca 2+]i in TRPV4-HEK 293 cells and VSMCs.This effect was not observed in vector-HEK 293 cells.In patch clamp experiments,BC/GD increased Ca 2+currents in TRPV4-HEK 293 cells,whereas no significant changes were observed in vector-HEK 293 cells.BC/GD dilated CBA contractions induced by U46619 and KCl,with a concentration-dependent increase of the dilatory effect.In the middle cerebral artery occlusion model,cerebral blood flow in the ischemic side significantly decreased,whereas BC/GD intervention significantly increased cerebral blood perfusion in the ischemic side,reduced the infarct area,and improved neurological function scores and neuronal damage.Conclusion:BC/GD activates the TRPV4 channel,leading to Ca ^(2+) influx,which in turn activates the intermediate conductance calcium-activated potassium channels channel to regulate vasodilation in vascular smooth muscle.
