Effects of U50,488 on LHb neuronal excitability required intact synaptic transmission. Insets: Example traces of AP generation in response to +50 pA current injection at baseline + synaptic receptor blocker/s (black) and post-synaptic receptor blocker/s + U50,488 (red). A-B. Complete fast-synaptic blockade of GABAARs (PTX), NMDARs (APV), and AMPARs (DNQX) (collectively referred to as SynBl) blocked the effects of U50,488 on AP generated across depolarizing current steps in Ih- and Ih+ neurons. C. DNQX prevented the effects of U50,488 in Ih- neurons D. U50,488 effect on excitability of Ih+ neurons remained intact with DNQX application. E-F. APV application blocked the effects of U50,488 in Ih- and Ih+ neurons. G-H. PTX application blocked the effects of U50,488 in Ih- and Ih+ neurons. *p < 0.05. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)