The effect of unsaturated fatty acids on sodium nitroprusside stimulation of guanylate cyclase in the human astrocytoma clone, D384, and the human neuroblastoma clone, NB1-G.

Sodium nitroprusside (SNP) stimulates cGMP formation to a greater extent in 20,000 g supernatant fractions of the human neuroblastoma clones NB1-G and SH-SY5Y than in the human astrocytoma clone D384. This suggests that these cell lines contain the soluble form of guanylate cyclase. Arachidonic, 8,11,14- and 11,14,17-eicosatrienoic acids inhibit SNP (10(-4) M)-stimulated cGMP formation more potently than the C18 unsaturated fatty acids linolenic and linoleic acids in D384 and NB1-G. In contrast the C20 saturated fatty acid, arachidic acid had little effect even at 10(-4) M concentration. In addition arachidonic and 8,11,14-eicosatrienoic acids inhibited basal guanylate cyclase activity, in NB1-G, over the same concentration range as they inhibited SNP-stimulated cGMP formation. No evidence could be obtained for the stimulation of guanylate cyclase by arachidonic acid in either NB1-G or D384. These results provide further support for suggestions that arachidonic acid or its metabolites may be important regulators of cGMP formation in the nervous system.