Figure 4: Capsazepine decreased glutamatergic synaptic activity of BLA in NMD slices through a presynaptic mechanism.

(a) Representative traces illustrating sEPSCs before and after the addition of capsazepine (CZP, 5 μM). (b) Cumulative fraction of interevent intervals of sEPSCs in one BLA pyramidal neuron under the pre-drug and post-drug conditions (left); bar plot showing the significant decrease of sEPSC frequency by CZP (right); frequency of CZP-treated neuron was normalized by that from the same neuron before CZP-treatment. (c) Cumulative fraction of peak amplitude of sEPSCs under the pre-drug and post-drug conditions (left); bar plot showing the significant decrease of sEPSC amplitude by CZP (right); amplitude of CZP-treated neurons was normalized by that from the same neuron before CZP-treatment. (d) Representative traces illustrating mEPSCs before and after the addition of CZP at 5 μM. Na⁺ channel blocker TTX (1 μM) was used to block action potential firing. (e) Cumulative fraction of interevent intervals of mEPSCs in one BLA pyramidal neuron under the pre-drug and post-drug conditions (left); bar plot showing the significant decrease of mEPSC frequency by CZP (left); frequency of CZP-treated neurons was normalized by frequency from the same neuron before CZP-treatment. (f) Cumulative fraction of peak amplitude of mEPSCs under the before-drug and after-drug conditions (left); bar plot showing that mEPSC amplitude was unaffected by CZP treatment (right); amplitude of CZP-treated neuron was normalized by amplitude from the same neuron before CZP-treatment. *P < 0.05 vs. Pre.