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. Author manuscript; available in PMC: 2019 Jun 1.
Published in final edited form as: Anesthesiology. 2018 Jun;128(6):1220–1236. doi: 10.1097/ALN.0000000000002191

Figure 4. Topical application of dermorphin [D-Arg2, Lys4] (1–4) amide (DALDA) attenuates both evoked and spontaneous activity in DRG neurons.

Figure 4

(A) Upper: GCaMP6 calcium imaging shows that topical application of DALDA (5 μM, 1 μL) to the lumbar DRG of pirt-GCaMP6 mice with chronic constriction injury (CCI) reduced the activity in small-diameter DRG neurons evoked by pinch stimulation at the ipsilateral hindpaw. Lower: Representative traces from three cells (red arrows) show that DALDA attenuated the calcium increase evoked by test pulses. Population data of evoked calcium activity in small-, medium-, and large-diameter neurons (n=5 experiments). (B) Upper: Topical application of DALDA (5 μM, 1 μL, n=5 experiments) to lumbar DRG also inhibited spontaneous activity mostly in small-diameter neurons (red arrowheads) of CCI mice. Lower: Population data of spontaneous activity in small-, medium-, and large-diameter DRG neurons. Data are shown as the number of activated neurons divided by the number of frames. One-way repeated measures ANOVA with Bonferroni post hoc test. #P < 0.05, ##P < 0.01 versus the indicated group, *P < 0.05 versus small-diameter neuron. Data are expressed as mean ± SD. ANOVA, analysis of variance; DRG, dorsal root ganglion.