Figure 7.
Refeeding and CCK8 downregulate CB1 expression in rat nodose ganglion. A, In situ hybridization of CB1 in rat nodose ganglion after fasting for 48 hr (dark-field images; rostral direction indicated by arrow; see also Fig. 6). B, In a fasted rat, refed for 2.5 hr, there is virtually complete loss of CB1 transcripts revealed by in situ hybridization. C, Similarly, there is loss of the CB1 signal revealed by in situ hybridization in nodose ganglion after 48 hr fasting and administration of CCK8 (10 nmol, i.p., 2.5 hr before killing). D, Administration of CCK is associated with phosphorylation of CREB in neurons that express CB1 (E). F, Overlay of D and E. G, Higher-power magnification (region indicated by box in F) shows that CB1-expressing neurons (green) respond to administration of CCK8 indicated by colocalization (open arrows) of nuclear phospho-CREB (H, red; I, overlay). J, Deconvolution microscopy of a single neuron showing CB1 immunoreactivity in cytosolic vesicles (filled arrows, red); K, nuclear phospho-CREB (open arrows, green); L, overlay. Scale bars: A–F, 100 μm; G–L, 25 μm.