Skip to main content
. Author manuscript; available in PMC: 2019 Jun 15.
Published in final edited form as: Biol Psychiatry. 2018 Jan 12;83(12):1012–1023. doi: 10.1016/j.biopsych.2018.01.003

Figure 2.

Figure 2

Vesicular glutamate transporter (VGluT2)-positive ventral pallidum (VP) neurons exhibit distinct membrane properties from canonical VP subtypes. (A) Experimental schematic. Floxed adeno-associated virus construct encoding enhanced yellow fluorescent protein (eYFP) was injected into the VP of VGAT-Cre, ChAT-Cre, PV-Cre, or VGluT2-Cre mice to selectively label genetically defined cell types in the VP. Using patch clamp electrophysiology, passive membrane properties were measured from parvalbumin (PV)-positive (PV+; n = 11), gamma-aminobutyric acid (GABA) type I (n = 14), and GABA type II (n = 14), choline acetyltransferase (ChAT)-positive (ChAT+; n = 8), and VGluT2-expressing (VGluT2+; n = 7) VP neurons. (B) Summary of average capacitance values (PV+ = 17.6 ± 2.3 pF, GABA I = 18.6 ± 1.7 pF, GABA II = 13.4 ± 2.6 pF, ChAT+ = 32.4 ± 2.1 pF, VGluT+ = 14.1 ± 1.3 pF), resting membrane potential (PV+ = −51.3 ± 1.6 mV, GABA I = −64.5 ± 1.5 mV, GABA II = −51.2 ± 2.8 mV, ChAT+ = −58.1 ± 1.8 mV, VGluT+ = −78.5 ± 2.8 mV), and firing rate (PV+ = 9.77 ± 0.89 Hz, GABA I = 0.47 ± 0.16 Hz, GABA II = 4.78 ± 0.42 Hz, ChAT+ = 2.03 ± 1.00 Hz, VGluT+ = 0.86 ± 0.75 Hz) is shown for each genetically defined population of VP neurons. VGluT+ VP neurons were significantly hyperpolarized, F4 = 27.24 p < .001, Tukey post hoc tests for comparison of VGluT against all other populations < .01. (C) For each genetically identified cell population, the number of action potentials per second in response to successive current injection (−40 to 200 pA) is plotted. Excitability was calculated as area under the curve. There was a significant effect of cell type on excitability (F4 = 25.08, p < .001); excitability was lower in VGluT2+ cells relative to all other subtypes (ChAT: t = 2.83, p = .011; PV: t = 6.62, p < .001; GABA type I: t = 3.57, p = .001; GABA type II: t = 2.20, p = .034). (D) Representative trace demonstrating spontaneous firing rate and waveform of genetically identified VP subpopulations. Scale bars for action potential trace: 10 mV, 20 ms. Scale bars for spontaneous activity trace: 10 mV, 1 s.