Figure 1.

Concentration-dependence curves for DEA/NO-stimulated cGMP accumulation on chromaffin cells. Cells were incubated for 30 min in Locke's solution containing 0.5 mM IBMX. Then they were stimulated for 10 min with the indicated DEA/NO concentrations and cGMP measured by radioimmunoassay. Results expressed as pmol /10⁶ cells, corresponding to the mean ± standard error of three experiments performed in triplicate, with different cultures. DEA/NO was freshly prepared every day in NaOH 0.01 N and its concentration checked by measuring the absorbance at 250 nm. Data were fit to sigmoidal representation by using Microcal Origing program.