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. 2005 Aug 10;25(32):7459–7469. doi: 10.1523/JNEUROSCI.1193-05.2005

Figure 2.

Figure 2.

CCK-8S activates orexin neurons. A, In the presence of TTX, many peptides were screened by bath application (Table 1). NPY (100 nm) and galanin-like peptide (GALP; 100 nm) had no effect (n = 20), although CCK-8S (100 nm) increased intracellular calcium concentration in the orexin neurons. Lines at the top of the graph show CFP and YFP intensity, respectively. Intensity of CFP fluorescence decreased while intensity of YFP fluorescence increased simultaneously when CCK-8S was applied. B, CCK-8S induced an increase in intracellular calcium concentration in a concentration-dependent manner. EC50 was 8.2 ± 2.6 nm (n = 20). C, D, Whole-cell current-clamp recording of orexin neurons showing that CCK-8S (30 nm) depolarized orexin neurons in the presence (C, bottom) or absence (C, top) of TTX (1 μm). D, Concentration dependency of the CCK-8S-induced depolarization in the presence of TTX. The EC50 and Emax were 7.7 ± 2.7 nm and 12.7 ± 1.7 mV, respectively (n = 10-15). E, Typical trace of CCK-8S-induced inward current under voltage-clamp recording at a holding potential of -60 mV. F, Concentration dependency of CCK-8S-induced inward current. EC50 and Emax were 3.3 ± 0.7 nm and 17.9 ± 1.4 pA, respectively (n = 10-15). Peptides were applied by bath application during the period represented by bars. Values are represented by mean ± SEM.