FIGURE 5.
PDE4B and PDE4D control a pool of cAMP in vicinity of CNG channels. Calcium influx in MEFs expressing the modified olfactory CNG channel (C460W/E583M) was measured to determine the effect of PDE4 variant ablation on cAMP accumulation in response to 100 nm Iso treatment. Intracellular calcium ([Ca2+]i) concentration was measured by ratiometric fura-2 fluorescence and is proportional to the local concentration of cAMP. A and B, knock-out of either PDE4D (A) or PDE4B (B) caused an increase in the membrane-associated cAMP accumulation in response to Iso stimulation. The number of individual cells analyzed (n) is given for each MEF cell culture. C, cells were untreated for basal measurements or treated with rolipram (Rol) (10 μm) for 15 min. The graphs report the mean ± S.E. of at least four separate experiments. Error bars, S.E.