Fig. 5.

cAMP modulation can be blocked by the protein kinase A inhibitor H-89. A, Responses to 10 msec flashes recorded in photoreceptors from WT photoreceptors in the absence and presence of phosphodiesterase inhibitor IBMX (100 μm), IBMX and protein kinase A inhibitor H-89 (1 μm), and H-89 alone (1 μm). B, C, Time-to-peak (B) and time-to-half-decay (C) of macroscopic light responses in control WT photoreceptors and in the presence of IBMX, IBMX and H-89, and H-89 alone. Although H-89 PKA inhibitor had no effect on its own, it eliminated the effect of IBMX on the response kinetics. Mean ± SD; n = 5–7 cells. *p < 0.05.