Figure 1.
CRF increased the firing rate of VTA dopamine neurons in the mouse The presence of Ih predicted dopamine content in mouse VTA neurons. A1, example neuron where a 250 ms hyperpolarizing voltage step from −60 mV to −120 mV elicited a slowly developing inward current. The magnitude of Ih was calculated by subtracting the instantaneous current (IS) from the steady-state current (SS) achieved during the voltage step. Scale bar vertical is 500 pA and horizontal is 100 ms. A2, 53/54 recorded neurons (red) with Ih co-localized with tyrosine hydroxylase immunohistochemical staining (green). A3, 1/54 recorded neurons with Ih did not co-localize with tyrosine hydroxylase. B, example neuron showing enhancement of VTA dopamine neuron firing by 10 min application of 1 μm CRF. Inset scale bar vertical is 20 mV and horizontal is 2.5 s. C, average effect of 1 μm CRF application (10 min) on firing rate of VTA dopamine neurons (n = 14). D, significant maximal increases in firing rate on dopamine neurons were observed with 1 μm CRF (n = 14) and 500 nm CRF (n = 6), but not with 100 nm CRF (n = 5). **P < 0.01, ***P < 0.001.