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. Author manuscript; available in PMC: 2023 Mar 1.
Published in final edited form as: Biol Psychiatry. 2022 Jun 22;93(2):197–208. doi: 10.1016/j.biopsych.2022.06.011

Figure 4.

Figure 4.

CCK is necessary and sufficient to potentiate caudally evoked but not rostrally evoked IPSCs. (A) Representative time course and example IPSCs evoked in a dopamine neuron with a stimulating electrode placed caudal to the VTA (diagram) before and during bath application of CCK (0.1 μM). (B) Averaged caudally evoked IPSC amplitudes before and during the presence of CCK (n = 8 cells/7 mice). (C) Caudally evoked IPSC amplitudes before and after application of CCK (n = 8 cells/7 mice, 3 cells from male mice, 5 from female mice). Paired t test, p = .04, df = 7. (D) Representative time course and example IPSCs before and after DEP+LFS in the presence of CCK. CCK (1 μM) was present for at least 20 minutes before DEP+LFS. (E) Time course of averaged IPSC amplitudes before and after DEP+LFS (n = 7 cells/5 mice). (F) IPSC amplitudes before and after DEP+LFS (n = 7 cells/5 mice, 2 cells from male mice, 5 cells from female mice). Wilcoxon paired test, p > .999. (G) Representative time course and example IPSCs evoked in a dopamine neuron with a stimulating electrode placed rostrally within the VTA (diagram) before and after bath application of CCK (0.1 μM). (H) Averaged rostrally evoked IPSC amplitudes before and after CCK application (n = 7 cells/5 mice). (I) Rostrally evoked IPSC amplitudes before and after CCK application (n = 7 cells/5 mice, 5 cells from male mice, 2 cells from female mice). Paired t test, p = .86, df = 6. Scale bars = 100 pA, 10 ms. CCK, cholecystokinin; DEP, depolarization; GFP, green fluorescent protein; IPSC, inhibitory postsynaptic current; LFS, low-frequency stimulation; LTP, long-term potentiation; norm., normalized; VTA, ventral tegmental area.