Fig. 6. Time course of N-acetylneuraminic acid (NANA)-stimulated cAMP content of tentacle ectoderm. Pre-starved anemones were pre-incubated in filtered, natural sea water containing 10^-4moll^-1 IBMX for 20min followed by incubation in filtered, natural sea water containing 10^-4moll^-1 IBMX and 1.8x10^-5moll^-1 NANA for specified times. Tentacles were excised, snap-freezen and assayed for ectodermal cAMP content as in Fig.4. Two sets of experiments were combined: one measured the cAMP contents between 0 and 5min of incubation with NANA (, N=3 experiments; n=36 samples) and the other between 5 and 45min of incubation with NANA (, N=3; n=22). The value for 5min of incubation was the average of means from the two sets of experiments. Data are expressed as fmolcAMPµg^-1protein. The number of sea anemones used in each experiment ranged between 18 and 20. Values are means ± S.E.M.