The Roles Of GABAergic Neurons Of Periaqueductal Gray In Regulating Active Avoidance Learning

The periaqueductal gray(Periaqueductal gray,PAG)is a significant brain region involved in defensive reactions(eg.flight,escape and freezing)which response to aversive emotion,including fear,threaten,anxiety and so on.So far,the neural mechanism of PAG in regulating active avoidance learning remains unknown.Objective: Our work aims to elucidate the roles of ?-tuminobutyric acid(GABAergic)neurons of PAG in regulating active avoidance learning.Methods: The experimental mice were trained in shuttle box to learn Active Avodiance(AA).The immunofluorescent staining was used to determine the c-fos,one member of immediately early genes(IEGs),expressed in PAG during AA learning.In order to inject the rAAV-Syn-hM3Dq-mCherry or rAAV-Syn-hM4Di-mCherry into PAG of Vgat-cre mice,the stereotaxic technique was applied.2-3 weeks after injection,hM3 Dq or hM4 Di were expressed on GABA neurons.300?m brain slices of the PAG were prepared for whole cell clamp-patch to record the electrophysiological responses of GABAergic neurons to the clozapine-N-oxide(CNO).Finally,r AAV virus injected Vgat-cre mice were tested in the shuttle box to investigate their AA learning ability basing on DREADD.Results: The establishment of AA learning was delayed in Vgat-ChR2-EYFP transgenic mice.In addition,the number of c-fos expressed GABAergic neurons in PAG increased as compared to control mice.The GABAergic neurons expressing hM3Dq-mCherry were specifically activated by CNO,consequently induced the increased frequency of action potential firing.By contrast,the neurons expressing hM4Di-mCherry were inhibited by CNO.In the AA learning process,specifically activating GABAergic neurons suspended AA.However,inhibiting GABAergic neurons had no effect on AA.Conclusion: Vgat-ChR2-EYFP transgenic mice showed a defect of AA learning.The GABAergic neurons of PAG modulated active avoidance behavior.Simultaneously,enhancing GABAergic neurons activity led to delayed acquisition of active avoidance behavior.