AgRP neuronal excitability determines connectivity of VTA dopamine neurons. (a,b) Representative traces, probability plots and average peak amplitude (insets) of miniature postsynaptic currents in control and AgRP-Sirt1 mice. (c) Dose response of GABA blockade on LTP propagation in control. (d) Saturating doses of GABA blockade (10 μM bicuculline (Bic), arrow in c) eliminated mIPSCs in both control and AgRP-Sirt1 mice. (e) AgRP-Sirt1 mice had increased LTP either in the absence of GABA blockade (No) or in the presence of saturating doses of GABA blocker (Sat). (f) Quantification of LTP during development in control and AgRP-Sirt1 mice. *P < 0.05, **P < 0.01, ***P < 0.001. Data are presented as mean ± s.e.m.