Fig. 6
Effects of α2-AdR antagonists on noradrenaline (NA)-induced inhibitory action. A: In the presence of the α2-AdR antagonist RS79948, the NA-induced inhibitory action was suppressed on average across all recorded data (n = 20). Right: Distribution of eEPSC amplitudes after 5–7 min of NA application. B: Five out of 20 data were less affected by the α2-AdR antagonist and clearly showed inhibitory effects in deep cerebellar nuclei neurons (filled circles, n = 5). This observation suggests that NA activated D2-like receptors (D2Rs) in these cases, as shown in the schematic drawing (right). In 15 out of 20 data, no effect of NA application was observed (open circles, n = 15). These results suggest that a subset of synapses in the deep cerebellar nuclei heterogeneously express DA receptors. Schematic drawing on the right shows “Non-responder” synapses with no or extremely low D2-like receptor expression under α2-AdR blockade conditions.
