Figure 3. The intracellular biosensor concentration does not affect the amplitude of the cAMP response.

The amplitude of the response to SKF38393 was quantified in individual neurones as a percentage of the maximal forskolin + IBMX response and was plotted against fluorescence intensity. Each data point corresponds to a region of interest drawn on a single neurone. Neurones recorded during the same experiment were plotted in the same colour. A, pyramidal cortical neurones expressing Epac2-camps300; 11 experiments. B, striatal neurones expressing Epac1-camps; 5 experiments. The linear regression was calculated for all the data points on the graph with slopes of 0.0040% AU⁻¹ (A) and 0.0054% AU⁻¹ (B), where AU represents arbitrary units.