Objective To explore the property of projection neurons in the pathway from the medial prefrontal cortex(mPFC)to the thalamic paraventricular nucleus(PVT)and to investigate the effect of modulation of the pathway on physiological pain and acute pain in mice.Methods Three knock-in mice with glutamate decarboxylase 67-green fluorescent protein(GAD67-GFP)were used in morphological tracing experiments,and twenty-seven C57 mice were used for behavioral observation experiments.Cholera toxin subunit B(CTB)was injected into the PVT of GAD67-GFP transgenic mice,and the properties of mPFC neurons projected to PVT were observed.The mPFC-PVT pathway was activated or inhibited by chemogenetics to observe the effects on physiological pain,such as mechanical pain,thermal pain,cold pain,and on acute inflammatory pain induced by capsaicin in mice.Results CTB-labeled neurons in the mPFC were mainly distributed in layer Ⅴ and layer Ⅵ and not double-labeled with GAD67-GFP.Chemogenetic activation of the mPFC-PVT pathway decreased the mechanical pain threshold significantly(P＜0.0001)and shortened the thermal pain latency(P＜0.001),but had no obvious effects on cold pain.Inhibition of this pathway increased the mechanical pain threshold significantly(P＜0.05).Activation of the pathway increased the paw licking time(P＜0.05)in acute inflammatory pain induced by capsaicin.Conclusion mPFC-PVT pathway is a non GABAergic projection and its activation can promote mechanical pain,thermal pain,and acute inflammatory pain induced by capsaicin in mice.
维普
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