Figure 2.
Postsynaptic calcium transients elicited by nicotine and hypocretin at a single spine in apposition with a thalamocortical terminal. A, Images show spines on a tertiary dendritic branch of a layer V pyramidal neuron (1) under baseline conditions and (2) during a nicotine-elicited (10 μm) postsynaptic calcium transient at the spine in apparent apposition to a thalamocortical terminal (inset). Red and blue graph lines show the green/red (G/R) intensity ratio obtained from regions of interest on the spines, indicated by the red and blue arrows, respectively. B, Images show spines (3) 30 min after nicotine washout and (4) during a hypocretin-elicited (100 nm) postsynaptic calcium transient. The graph shows hypocretin-elicited changes in G/R intensity ratio at the same spines as above. Scale bar, 2 μm. C, Image showing (5) high calcium elicited by a burst of action potentials. Scale bar, 5 μm. The graph shows control series of images acquired without application of neurotransmitter or drug. The arrow indicates a brief depolarizing current injection used to elicit the burst of spikes. D, The bar graph at the bottom right shows peak Z-scores (mean ± SEM) for G/R ratio in spines with (n = 6 spines) and without (n = 31 spines) apparent thalamocortical (TC) appositions in response to nicotine, hypocretin, and the burst of spikes. Error bars represent SEM. Nic, Nicotine; Hcrt, hypocretin.
