Figure 5.
Diminished inhibitory effect of ISO on excitability of CeM neurons from CaV3.1 KO mice. A, Original traces from a representative WT neuron in the CeM before application of ISO (black), after application of ISO (gray) and after wash (light gray trace) with active membrane responses to a depolarizing (100 pA) current injection. B, ISO reduced tonic action potential firing frequency across all current pulses (5 cells, 3 animals; from 50 to 200 pA, two way RM ANOVA: interaction F(6,24) = 0.98, P = 0.460, current injection F(6,24) = 27.55, P < 0.001, ISO effect F(1,4) = 17.18, P = 0.014). C, ISO reduced RMP (6 cells, 3 animals; paired two-tailed t-test: t(5) = 3.48, P = 0.018) in WT mice. D, ISO did not change IR (paired two-tailed t-test: t(5) = 1.29, P = 0.252) in WT mice. E, Original traces from a representative CeM WT neuron showing post-inhibitory rebound burst-firing before (black), after application of ISO (gray) and after wash (light gray trace). Burst-firing was induced by injection of a hyperpolarizing (−150 pA) current during 400 ms. F, Averaged LTS amplitude was reduced by the application of ISO across all hyperpolarizing current pulses from −25 to −225 pA in WT mice (7 cells, 3 animals; two-way RM ANOVA: interaction F(8,48) = 2.70, P = 0.015, current injection F(8,48) = 20.56, P < 0.001, ISO F(1,6) = 18.08, P = 0.005, Sidak’s post hoc presented in figure). G, Bar graph showing ISO significantly increased the threshold for the occurrence of LTS (6 cells, 3 animals; paired two-tailed t-test t(5) = 5.98, P = 0.002). H, ISO had very little effect on average tonic firing frequency in CaV3.1 KO mice (6 cells, 3 animals; two way RM ANOVA: interaction F(6,30) = 8.07, P < 0.001, current injection F(6,30) = 83.00, P < 0.001, ISO effect F(1,5) = 4.36, P = 0.091, Sidak’s post hoc presented in figure). I and J, ISO did not affect RMP (paired two-tailed t-test: t(5) = 1.25, P = 0.268) and IR (paired two-tailed t-test: t(5) = 1.46, P = 0.203) in CaV3.1 KO mice. *P < 0.05, **P < 0.01, ***P < 0.001.